California PATHPartners for Advanced Transit and Highways

Year 2000

California PATH – Partners for Advanced

Transit and Highways – is a collaboration

between the California Department

of Transportation ( C a l t r a n s ) , the

University of California, other public and

private academic institutions, and

private industry. PATH’s m i s s ion :

applying advanced technology to

increase highway capacity and safety

and to reduce traffic congestion, air

pollution and energy consumption.

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California PATH

Director’s Introduction 3

A Word from Caltrans 5

Overview of California PATH 7

Research — ATMIS 13

Research — AVCSS 17

Recent PATH Publications 23

Publications Order Form 29

California PATH Database 31

Partners for Advanced Transit and Highways

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Director’s IntroductionThe California PATH Program, a collaboration between Caltrans andthe University of California, is a unique multidisciplinary researchprogram that seeks advanced technological solutions to our wors-ening transportation problems. PATH’s researchers and staff comefrom many countries and academic backgrounds and are spreadacross California’s college campuses and into private industry. Theyare united by the goal of fulfilling the promise of ITS, IntelligentTransportation Systems, and finding solutions for today and tomorrow.

Caltrans and PATH share a vision of congestion relief through high-way automation. PATH’s demonstration of an eight-car fully auto-mated platoon, as well as the Honda/PATH magnetic/computer-vision guided vehicles, were highlights of the most successful dem-onstration of vehicle automation technology ever held: Demo ’97.PATH has since participated in follow-up automation technologydemonstrations, including Demo ’98 in the Netherlands, Demo ’99in Ohio, and Demo 2000 in Japan. Caltrans and PATH are currentlyplanning for a major demonstration in 2003 that will showcase au-tomation technology for heavy trucks and buses.

PATH’s research activities in the area of Advanced Traffic Manage-ment and Information Systems (ATMIS) have greatly expanded inthe last few years. An exciting new Center for Commercialization ofITS Technologies (CCIT) will open in the 2001 near the Berkeley cam-pus. CCIT will team up University faculty and graduate students, pri-vate sector companies, and government transportation agencies ina new facility with the mission of facilitating the commercial deploy-ment of advanced traffic information system technologies.

PATH brings together engineers and economists, geographersand urban planners, computer scientists and statisticians,among others. Its multidisciplinary atmosphere is responsiblefor shaping the “modern” transportation engineer, who is familiarnot only with traditional disciplines but also with the emerging areasof sensors, communications, data structures, vehicle dynamics andcontrol, and many other disciplines. We pride ourselves on the manystudents and postdocs who have “graduated” from PATH and goneon to influential positions at universities and in the public and pri-vate sectors, spreading the ITS vision. PATH’s future looks bright asthe need for intelligent transportation solutions becomes ever moreclearly apparent. Bringing together the best minds in California toimprove California’s, the nation’s and the world’s transportation sys-tems is PATH’s goal!

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A Word from Caltrans

Caltrans DirectorJeff Moralesvisited PATH inthe spring andwas so impressedwith PATHresearch that hereturned in thefall with theCaltrans DistrictDirectors andtheir staffs.

The collaboration between Caltrans and PATH has now evolved into a world re-nowned transportation research program that investigates new technological meth-ods to improve traveler safety, reduce traffic congestion, enhance the mobility ofpeople and goods, and increase our transportation systems’ economic productiv-ity. PATH’s future looks bright indeed as the need for deployed Intelligent Transpor-tation Systems (ITS) becomes more clearly apparent.

Transportation demand continues to accelerate at a pace that has over-whelmed our ability to build additional capacity. This capacity can, however,be increased by efficiencies made possible by recent improvements in elec-tronics, computers, communications, controls, sensors, and actuators thathave made these technologies more usable in widespread ITS applications.Our prime objective now is to implement the research products that wehave created in these past few years.

We are committed to building transportation systems that improve trafficflow, information gathering, and roadway safety. The Performance Measure-ment System (PeMS) project is one example that shows significant poten-tial benefits. PeMS technology will make real-time traffic conditions avail-able by converting raw loop detector data into information that is easilyaccessible and understandable by transportation system managers. Thisinformation will enable managers to make the right decision when choosing,for example, how to respond to an incident or when to schedule mainte-nance lane closures.

Despite our past successes, we know that further challenges remain if weare to maximize efficiency in the operation of our transportation systems.

In order to design safe and effective Advanced Vehicle Control and SafetySystems, designers will need to continue their efforts to derive solid quanti-tative knowledge of the driving environment and of how drivers will usethese systems. A great deal of fundamental data gathering, design, andreal-world test and evaluation will be necessary to expand the knowledgebase. This important work will advance us beyond the stage of theoreticalstudies and towards practical experimentation. Caltrans and PATH also re-main focused on our plan to demonstrate fully automated heavy vehicles inSan Diego in the summer of 2003.

It is my firm belief that this demonstration of bus and truck automation willbe a giant step forward in our goal to promote widespread deployment ofAutomated Highway Systems that support all vehicle types.

On behalf of the staff and management of Caltrans, I congratulate PATH onits substantial accomplishments during another successful year.

Greg LarsonCaltrans Management Liaison

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PATH Overview

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PATH Research

PATH Overview

Overview of California PATHThe California Partners for Advanced Transit and Highways Program (PATH) hasbeen leading the way in ITS (Intelligent Transportation Systems) research sincePATH’s founding in 1986, before the term ITS or its predecessor IVHS (IntelligentVehicle Highway Systems) had even been coined. PATH’s purpose is to developfoundations for the widespread adoption of advanced technologies that will im-prove the operation of California’s surface transportation systems. PATH’S pri-mary goals are to reduce traffic congestion and improve traffic safety. By suc-ceeding at these, we also expect to help reduce travel stress, pollution, and en-ergy consumption, and contribute to enhancing the strength of California’seconomy.

Caltrans provides the seed funding for PATH’s core research, based on its goal ofpromoting the development of new knowledge and new technology that canimprove the productivity, safety, and environmental impacts of California’s sur-face transportation systems.

PATH’s charter includes the missions of conducting leading-edge research, evalu-ating operational tests, developing public/private/academic partnerships, andeducating students as well as practitioners about ITS.

PATH focuses on research with the potential for dramatic improvements in theoperation of California’s transportation system, rather than diffusing its efforts inareas where only incremental improvements are possible. California’s populationand its transportation demands are growing so rapidly that the effects of incre-mental solutions would likely be absorbed by the time they could be imple-mented. Hence, PATH emphasizes relatively long-term, high-impact solutions.But PATH also addresses the progressive steps needed to achieve those long-term solutions. PATH research also attempts to identify impediments to progress,both technical and institutional, and to devise strategies for overcoming thoseimpediments. Research and development done under PATH auspices include:

■ identification of problems and needs

■ basic research on enabling technologies

■ applied technology research and development

■ system-level design and evaluation

■ experimental verification of design predictions

■ evaluations of existing technologies or equipment

■ evaluations of costs and benefits

■ technology assessments

■ predictions of users’ behavioral responses

■ predictions of the impacts of technologies’ use

■ evaluations of legal and institutional issues.

PATH is managed by the Institute of Transportation Studies of the Univer-sity of California at Berkeley, which established the PATH Program HeadquartersOffice at the University’s Richmond Field Station in 1986. Policy issues are ad-dressed by the PATH Executive Committee, composed of representatives of theprimary participating universities, and by the Caltrans-PATH Joint Management

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PATH Overview

Team, composed of program managers from both Caltrans and the University.PATH’s day-to-day operations are managed by the headquarters staff.

PATH headquarters has about forty full-time staff members, including a core groupof research staff members, plus program managers and administrators. A sub-stantial body of research is done by the full-time research staff at PATH headquar-ters, but most PATH research work is done by faculty members employing gradu-ate students on the campuses of the universities that form the PATH partnership.This work is supplemented by subcontracts to private companies as needed, andby cooperative research agreements with a variety of organizations, includingprivate companies as well as public institutions, both domestic and international.The product-development-oriented work of private companies complements themore basic work of the academic researchers, so that each group can concen-trate on what suits it best. Publication of PATH research work is coordinated atPATH headquarters.

PATH Activities in National and International ITS Programs PATH has receivedsubstantial funding from the Federal Department of Transportation (USDOT),including support from the Federal Highway Administration, Federal Transit Ad-ministration, and National Highway Traffic Safety Administration on a variety ofprojects that predated current Federal ITS programs. PATH participation in USDOTITS programs during the past year includes several projects within the IntelligentVehicle Initiative (IVI) program:

■ Evaluation of concepts for sensor-friendly vehicle and roadwaysystems, with Bechtel and Carnegie Mellon University.

■ Defining the requirements for a transit bus Forward Collision WarningSystem, with the San Mateo County Transit District (SamTrans, Caltrans,and bus manufacturer Gillig.

■ Transit bus Rear Collision Warning System requirements definition, withAnn Arbor Transit Authority and ERIM International.

■ Development of threat assessment simulation software for AutomotiveCollision Avoidance System (ACAS) field operational test with GeneralMotors and Delphi Automotive Systems.

PATH and Caltrans continued to participate in the Multistate Operations ResearchProgram (MORIP), which includes Minnesota, Texas, and Washington. MORIPprovides an opportunity for operations practitioners and researchers to shareinformation on ITS-related efforts in the four states. In 2000, the group devel-oped a business plan that, among other items, identified areas of common re-search interest. Subsequently, PATH and the Texas Transportation Institute (Texas

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PATH Research

PATH Overview

A&M University) have launched a joint investigation of the state of the practicein three areas: transportation systems performance measurement and data col-lection technology needs, data sharing policies and practices, and highway main-tenance management systems.

PATH has worked closely with Caltrans on developing two multistate pooled fundprojects to advance the state of the art of cooperative Advanced Vehicle ControlSystems (AVCS), with USDOT participation. Within the IVI Infrastructure Consor-tium, Caltrans and PATH have teamed with counterparts in Minnesota and Vir-ginia and automotive supplier Visteon to develop a cooperative intersection de-cision support system. Separately, as an outgrowth of the Phoenix Project,Caltrans and PATH have attracted ten other states to join in a Cooperative Ve-hicle-Highway Automation Systems (CVHAS) project, which we hope will revivenational interest in automated highways.

Evaluations of California ITS Operational Tests PATH has served as evaluator forthe following Field Operational Tests: • TravInfo (Bay Area) • Smart Call Box (SanDiego) • Adaptive Traffic Control (Anaheim) • Integrated Ramp/Signal Control(Irvine) • Mobile Surveillance (Orange County) • Wireless Spread Spectrum Com-munication (Los Angeles) • TransCal (Bay Area to Reno)

State-Funded Core Program of ITS Research The core of the PATH program is itscollection of research projects funded by Caltrans’ New Technology and ResearchProgram. Currently there are about ninety-five such projects, selected on thebasis of an annual Request for Proposals (RFP) and proposals submitted fromthroughout California. These involve the work of about forty professors, repre-senting fifteen academic departments on fourteen different university campuses,supervising the research of more than one hundred graduate students and post-doctoral researchers. Projects are currently being conducted at: UC Berkeley, UCDavis, UC Irvine, UC Los Angeles, UC Riverside, California Polytechnic State Uni-versity at San Luis Obispo, California State University San José, the ClaremontGraduate School, the Massachusetts Institute of Technology, Ohio State Univer-sity, Stanford, Texas A&M, the University of Michigan, and the University of South-ern California.

New projects PATH attracted research support from a variety of sources duringthe past year. Some of the new projects under development, in addition to theIVI projects previously cited, include: • A new simulation and visualization modelfor evaluation of Bus Rapid Transit Systems (SmartBRT), under the joint sponsor-

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PATH Overview

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PATH Research

PATH Overviewship of the Federal Transit Administration and Caltrans. • Develop-ment and evaluation of a variety of technologies for Bus Rapid Tran-sit, under Caltrans sponsorship and in cooperation with the SantaClara County Valley Transit Authority. • New technology approachesfor railroad crossing warnings at uncontrolled crossings in the SanJoaquin Valley, under sponsorship of the Caltrans Rail TransportationProgram. • A precision automatic steering control system for aCaltrans rotary snow blower, under the sponsorship of Caltrans’ Ad-vanced Highway Maintenance and Construction Technology pro-gram (AHMCT). • A project on distributed autonomous agent net-works of aerobots for the Office of Naval Research. • A testbed andautomotive example application project for Model-Based Integrationof Embedded Systems (MoBIES), under the sponsorship of the De-fense Advanced Research Projects Agency (DARPA).

The Caltrans Traffic Operations Program supplemented PATH’s coreprogram with a package of special projects related to its Traffic Op-erations Plan Strategies (TOPS) initiative, including:

• Further development and extension of the Performance Measure-ment System (PeMS) to Caltrans District 7 (Los Angeles) and otherdistricts. • Initial quantification of TOPS impacts using PATH’s ITSbenefits/costs methodology and sample applications on the ATMSTestbed network in District 12 (Orange County) using the Paramicstraffic simulation model and other Testbed simulation tools. • Ex-pansion of Testbed facilities to allow for transportation managementcenter (TMC) operator training. • Focused investigations of variousfreeway traffic flow and control issues and development of perfor-mance improvement approaches.

Other notable developments during the past year included: • Found-ing PATH’s Center for Commercialization of ITS Technologies (CCIT),to encourage the intermediate steps that need to be taken between

research and deployment of ITS technologies and systems.Hamed Benouar was appointed CCIT Executive Director. • Re-ceiving the ITS America Award for Best Research Project,awarded to PATH’s Enhanced Loop Detector Project for its in-novative use of inductive signature analysis techniques. • Par-ticipating in SmartCruise Demo 2000 in Tsukuba City, Japan,under the sponsorship of Japan’s Ministry of Construction. Oneof only three non-Japanese organizations invited, PATH dem-onstrated how our magnetic marker guidance system can beused as the basis for integrated services of lane departure warn-ing, lane departure prevention, driver lateral guidance, andautomatic steering.

Together with the IntelligentVehicle TransportationProgram, Caltrans andSamTrans, PATH’s ForwardCollision Warning Systemproject defines requirementsfor a system to alert a publictransit driver to unseenobstacles. Sensors mountedon the bus collect data. Indeveloping an optimalsystem, radar, light radar,sonar or video may beemployed.

PATH Research

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PATH Research

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ATMSAdvanced TransportationManagement Systems

Traffic Data CollectionTechnologiesNew traffic data collection proto-types are continually being de-veloped and field tested. Newdetection systems developed bythe universities made their way tothe freeways for real world test-ing.

Development and Testing of Field-Deployable Real-Time Laser-BasedNon-Intrusive Detection Systemfor Measurement of True TravelTime on the HighwayMOU 3005 – Harry Cheng, UCDA laser-based field prototype wasdeveloped and tested on the high-way. Several field tests were donewith the prototype system on thehighway: results verified that theprinciple of the detection system istechnically sound and the system isreliable during all environments.

Field Investigation of AdvancedVehicle Reidentification Tech-niques and Detector TechnologiesMOU 3008 – Stephen Ritchie, UCIThe loop signature system for ve-hicle reidentification was tested at amajor signalized intersection to de-velop capabilities for on-line real-time intersection level of service es-timation. The capability also pro-vided the means to track the turningmovements of the vehicles at theintersection.

Field Operational Test of GPS andCellular Technologies for VehicleProbesMOU 3015 – Y.B. Yim, PATHCellular phone and GPS technolo-gies were evaluated for the vehicleas probes concept in the San Fran-cisco Bay Area. Two sample data setsprovided by US Wireless demon-strated that cellular phone trackingshow promise but needs further stud-ies to determine its ability to pro-duce reliable travel times. The GPSfield tests demonstrated higher ac-curacy, but differentiating betweenfreeways and frontage roads can beproblematic.

Development of a Cost-Effective Sur-veillance System in Caltrans District 4MOU 382 – Joy Dahlgren, PATH

A T M I SAdvanced Traffic Management Information Systems

The feasibility of using toll tag(FasTrak) equipped vehicles asprobes to estimate travel times inthe Bay Area was studied. The re-search found not only that using tolltag equipped vehicles as probeswould indeed be feasible in manyparts of the Bay Area, but that theygenerally cost less both in terms ofcapital and operating costs thanmany competing surveillance op-tions such as loop detectors, micro-wave and video detection. The con-gested areas near the bridges, whereloop detectors are not feasible, areprime candidates for toll tag probereaders.

Traffic EstimationUsing various advanced detec-tion technologies will yield newand more accurate forms of traf-fic data to help manage the trans-portation network, and helpdevelop and calibrate improvedtraffic flow theories and models.Freeway Performance Measure-ment System, Phase IIMOU 3012 – Pravin Varaiya, UCBPATH’s freeway performance mea-surement system (PeMS) was imple-mented in more Caltrans districts,District 7 in Los Angeles being thelatest. This allows Caltrans to mea-sure their performance in real time.PeMS presents information in vari-ous forms to assist managers, trafficengineers, planners, freeway users,value added resellers (VARs), andresearchers. The system also esti-mates travel times and fastest routefor the driver.

Improving Operations, Driver In-formation and Safety Using Ad-vanced Surveillance Metrics, Wire-less Communication and ExistingTraffic Detectors/ControllersMOU 3010 – Ben Coifman, PATHA new traffic surveillance strategyusing existing detectors to identifywhen the link between two detectorstations becomes congested wasdeveloped. A vehicle reidentificationalgorithm was developed for con-secutive detector stations on a free-way matching a vehicle measure-ment made at a downstream detec-tor station with the vehicle’s corre-sponding measurement at an up-stream station to provide travel timeinformation. The method was illus-trated using measured vehiclelengths from paired loop detectorspeed traps.

Real-Time Algorithms for TravelTime and Origin-Destination Esti-mates, Incident and VerificationMOU 353 – Alex Skabardonis, UCBPATH has mounted 12 fixed videocameras and 2 pan/tilt/zoom cam-eras on the top of a 320 foot tallbuilding adjacent to I-80 inEmeryville. The fixed cameras pro-vide a continuous view of I-80 be-tween the Bay Bridge approach andUniversity Avenue over 2 miles offreeways, interchanges, and front-age road. The video is being used forresearch in video image processesand modeling traffic flow dynamics.

Traffic Data Measurement andValidationMOU 3000 – Ben Coifman, PATHMany researchers have sought bet-ter estimates of velocity from single-loop detectors. Earlier work empha-sized post-processing techniques toreduce the bias from long vehicles inmean velocity estimates. This projecttook a different approach, using anew aggregation methodology toestimate median velocity. It wasshown that the estimate is lesssensitive to the presence of longvehicles. Furthermore, the proposedmethod of estimating median veloc-ity is simple enough that it was shownthat it could be deployed on existingtraffic controllers.

Traffic ManagementStrategiesIt is a well known fact that it isvery difficult to build or expandfreeways because of land, envi-ronmental and other constraints.Therefore, it is vital to researchways to manage the existingtransportation network as effi-ciently as possible.

Access Control Strategies to Man-age Traffic Backups and IncreaseSystem CapacityMOU 3004 – Carlos Daganzo, UCBExtensive field observations of amulti-lane freeway traffic upstreamof an oversaturated off-ramp wasperformed. It is based on empiricalevidence from freeway I-880 (north-bound) near Oakland, California. Themain finding of this research is evi-dence that a bottleneck caused byan off-ramp on a multi-lane freewaycan reduce the capacity down streamof the bottleneck significantly belowthe capacity of the freeway. Empiri-cal evidence gathered during the

Loop Detector SignatureReidentification

Fastrak Transponder used as TrafficProbe

Cameras Placed on top of thePacific Park Plaza Building

PATH Research

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from spilling over to the exit lane (bychanging the logic of a nearby trafficsignal), much higher flows were sus-tained on the freeway segment, anda bottleneck did not arise there. Theseobservations underscore the valueof control strategies that enable di-verging vehicles to exit a freewayunimpeded.

Simulation and ModelingTraffic simulation and modelingis essential in answering “whatif” scenarios for ATMIS applica-tions. In the past year, emphasiswas put on the Paramics modelto simulate the benefits of ATMIS.

Integrating a ComprehensiveModal Emission Model into ATMISTransportation Modeling Frame-worksMOU 381 – Matt Barth, UCRResearch done at UC Riverside hasintegrated a detailed emission model(CME/EC) with the Paramics simula-tion model. After successfully com-pleting this integration, two casestudies were carried out using thisPARAMICS/CME-EC tool. The firstcase study examined the emissionsimpact of HOT lanes along the SR-91corridor in Southern California. Theother case study examined the emis-sions impact associated redesignat-ing uphill lanes on I-60 near River-side, California. These case studiescan serve as examples as how toapply this new tool for creatingmicroscale emission inventories.

Bay Area Simulation and RampMetering StudyTO 4106 – Joy Dahlgren, PATHA project was initiated at PATH toevaluate ramp metering in the I-680Sunol Grade corridor. The entire cor-ridor was coded and carefully cali-brated in Paramics and now is readyto assess the effects of ramp meter-ing and any other strategies in the I-680 corridor.

ATISAdvanced Traveler InformationSystems

Will increase mobility and safetyby informing travelers and com-mercial vehicle operators of travelconditions and alternatives.

first year of this study strongly sug-gests that new, “smart” traffic con-trol approaches such as lane assign-ment can be used to relieve recur-rent congestion caused by divergebottlenecks.

Development and Evaluation ofAdaptive Ramp MeteringMOU 3013 – Michael Zhang, UCDA conceptual evaluation was doneon existing ramp metering algo-rithms including SWARM, METALINEand the Ball Aerospace algorithm.Several existing ramp metering al-gorithms were chosen to be the mostpromising and were simulated usingthe Paramics traffic simulation. Un-der high demand pressure, criticalconditions on the freeway demandlower metering rates, which oftenleads to long queues at meteredramps. When the size of the queueon metered ramps become long, it iscustomary for these algorithms toraise the entrance flow from rampsto a higher level till the long queuessubside. This often creates a high/low cycle effect in ramp meteringrates.

Development of Tools to Assessthe Effects on Traffic Safety ofChanges in Traffic Flow Conditionsunder ATMS OperationsMOU 3007 – Tom Golob, UCIAn evaluation tool was developedbased on identification of the salientrelationships between accident ratesand characteristics and traffic flowpatterns. The data for the underly-ing analyses involved one year ofaccidents on six major freeways inOrange County, combined with traf-fic flow conditions extracted fromloop detectors near the accident.The data was analyzed and partitionto different regimes such as time ofday, weather and traffic conditions.

Examining How ATMIS Can In-crease Freeway Bottleneck Capac-ityMOU 3011 – Mike Cassidy, UCBA study was performed to show howAdvanced Transportation Manage-ment and Information Systems(ATMIS) might be deployed to in-crease bottleneck capacities. Thestudy relied solely upon empiricalobservations from video taken in Or-ange County. A bottleneck with di-minished capacity arose wheneverqueues from an off-ramp spilled overand occupied the segment’s man-datory exit lane. Notably, wheneverthe off-ramp queues were prevented

ATIS for Ground-to-Air Connec-tivityMOU 3003 – Randolph Hall, USCA collaborative effort with UnitedParcel Service and Caltrans was doneto evaluate information services tar-geted at assisting overnight carriersin routing their trucks, schedulingtheir shipments, and optimizing theirdeparture times for the airport. Mod-els were developed for the airportterminal as a queueing process withrandom bulk arrivals. From thesemodels, performance measures weredeveloped for the process.

Consumer Research on ATIS Tech-nologies: Surveys of ATIS UsersMOU 363 – Y.B. Yim, PATHTwo studies related to the TravInfoEvaluation project was conducted.The second wave of the Broad Areasurvey determined the effect TravInfohad on the general public after it hadbeen operational for over a year. Thesecond wave of the Traveler Advi-sory Telephone System (TATS) sur-vey determined that people are stillcalling the TATS and are satisfiedwith the service.

Financing Plan for Public Sup-ported ATISMOU 364 – Y.B. Yim, PATHAn institutional analysis was doneabout alternative approaches to sus-taining publicly supported ATIS. Al-ternative revenue models were iden-tified that may be able to support theoperation of the newly created trav-eler information centers in the post-field operational test phase. Themarket potential for privately offeredadvanced traveler information ser-vices in the United States and Europeis; however, yet to be determinedsince consumer purchase behaviorfor traveler information is largelyunknown.

APTSAdvanced Public TransportationSystems

To address the transportationneeds of today and the future,California needs creative and in-novative solutions that providealternatives to reduce traffic con-gestion, promote equity and flex-ible travel, cut air pollution, andlink customers to public trans-portation. The PATH vision inte-grates technologies and alterna-

Ramp Metering

Increasing Bottleneck Capacity

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tive transit strategies with con-ventional transit service to im-prove mobility and reduce con-gestion.

Assessing Opportunities for Intel-ligent Transportation Systems inCalifornia’s Passenger IntermodalOperations and ServicesMOU 375 – Mark Miller, PATHA project was done to recommendstrategies for the improvement ofpassenger intermodal operations andservices, both by evaluating the cur-rent state of passenger intermodalismin California and by identifying waysthat intelligent transportation sys-tems can be used to enhance theservices currently in place from boththe user and institutional perspec-tives. A total of thirteen site visitswere conducted at passengerintermodal transfer facilities in theSan Francisco Bay Area, metropoli-tan San Diego, and the SacramentoArea. Each site visit considered fourstages of the intermodal transfer ex-perience: approach to the facility,the ticketing process, the transferwithin the facility and departure fromthe facility.

Consumer Research on Personal-ized Demand-Responsive TransitServiceMOU 398 – Y.B. Yim, PATHA study was done to conduct con-sumer research on personalized de-mand-responsive transit service(PDRT). The results of six focus groupsand the survey indicate that the ideaof a personalized transit service mayappeal to commuters as well as non-commuters. There is significant po-tential to attract travelers to PDRT. Amajority of these people were willingto pay between $5-$10 for a 30minute trip.

Evaluating the Impact of ITS onPersonalized Public TransitMOU 3002 – Maged Dessouky, USCAn investigation was done on the useof ITS technologies to improve theservice efficiency of demand respon-sive transit(DRT) providers and toevaluate the different opportunitiesit creates to improve the overall per-formance of DRT systems. Differenttechnologies that have been imple-mented or are being considered forimplementation by the transit pro-viders were reviewed. Technologiesthat have been implemented includeAVL, advanced wireless communica-tion, MDT, computerized vehiclenavigation, and geographic data-

base. Emerging technologies thathave potential for implementationinclude internet dispatching,superphones, personal data assis-tants, and smartmaps. It is antici-pated that the responsiveness andcosts of demand responsive transitmay be improved by utilizing theseITS technologies.

Expanded, Year-Two Carlink Dem-onstration: A User, Economic, andInstitutional Evaluation of “Smart”CarsharingMOU 3009 – Susan Shaheen, PATHCarLink II is a pilot project with 27Honda Civic vehicles in the Palo Altoarea. It follows the successful dem-onstration of the carsharing conceptof Carlink I in the Dublin/Pleasantonarea with the BART system. CarlinkII will determine its ability/potentialto transfer viable smart technologiesand business models to other loca-tions. New business employers andCaltrain have been secure in the PaloAlto area for this project. Also, newtechnologies have been developedfor the reservation system and track-ing the vehicle usage.

Decision Support &

Benefit Cost Analysis

Evaluation Methods for Measur-ing the Value of ITS Services andBenefits from ImplementationMOU 3001 – David Gillen, UCBITS transportation professionals facea difficult task in assessing benefitsand costs associated with ITS projectsand measuring system performance.This project undertook specific evalu-ations in two different areas of ITSapplication: (1) public transporta-tion operations with specific consid-eration of AVL applications and (2)freeway service patrol and emer-gency management.

ITS Evaluation WebsiteMOU 355 – Joy Dahlgren, PATHThis was a year of maturing, rede-sign, and redirection for the website.The name of the site was changedfrom LEAP to the more descriptiveITS Decision. The page format hasbeen redesigned and the home pagenow includes new graphics, new in-dexes, a featured new addition tothe site, and information on newadditions.

CarLink II

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A V C S SAdvanced Vehicle Control and Safety Systems

Vehicle ControlControl of Heavy DutyVehiclesRobust Lateral Control Of HeavyDuty VehiclesTO4201/MOU385–MasayoshiTomizuka, UCBThis project implements and testspreviously developed lateral controlalgorithms for heavy-duty vehicles,and enhances robustness and per-formance of lateral controllers. Toenhance robustness, a physical modelof the steering subsystem was de-rived and a nonlinear robust innerloop controller was designed. Anadaptive robust controller was thendesigned and proved by simulationto be robust under large model un-certainties while maintaining ridecomfortability. Simulations alsoshowed that the controller was ro-bust under various aerodynamic(crosswind) and loading conditions.Experimental evaluation of the ro-bust controllers for lane followingwas also conducted. The emphasisfor the experiments was to evaluatethe robust controllers under varyingroad and loading conditions.

Integrated Longitudinal ControlFor Safe Automation Of Com-mercial Heavy VehiclesTO4202/MOU393–AnnaStefanopoulou, Univ. of Michi-gan; Christian Gerdes, StanfordThis project builds on the results ofprevious PATH projects on the longi-tudinal control of heavy-duty ve-hicles. The project considers two mainobjectives. The first objectives dealswith the robust longitudinal controldesign through on-line adaptation,so that the performance of the auto-mated heavy truck will be insensitiveto varying load and road conditionssuch as changes in vehicle mass, loadvariations, road grade, wind gusts,and engine tuning. Simulation mod-elling and sensitivity analysis of thelongitudinal control law to changesin mass, grade, rolling resistance andaerodynamic drag have been com-pleted. The results indicate that massand grade are of significant impor-tance to performance while varia-tions in drag and rolling resistanceare minor. Experimental verificationon the new control modules will beperformed. The second objective isto investigate the use of the enginebrake and transmission retarder for

braking, and to design controllersthat are capable of combining all thedifferent brake actuators for optimalperformance. To enhance the ro-bustness and safety of the integratedcompression braking mechanismwith the friction brake controller pre-viously developed, a model refer-ence algorithm for the compressionbraking controller is developed. ThePATH Freightliner truck is being in-strumented for experimental testingand verification of the control de-signs.

Control Of Heavy-Duty Vehicles:Environmental And FuelEconomy ConsiderationsTO4203–Petros Ioannou, USCThis project evaluates the environ-mental performance of existing andpreviously developed heavy-dutyvehicle following control systems,and develop new designs, wherenecessary, for environmentally effi-cient controllers using an emissionsand fuel consumption model forheavy trucks being developed at UCRiverside with support from PATHand the U.S. EPA. The controllers willguarantee fuel efficiency and alsostability of close vehicle following.The emissions model will first beused to examine the environmentalimpact of the current longitudinalcontrol laws during traffic distur-bances in a mixed traffic. The dataand the environmental performanceresults will then be used to developmodifications to existing controllersor design new controllers. Simula-tions and a sequence of experimentsusing actual vehicles will be per-formed to validate the results.

Vehicle Control Under AbnormalConditions Vehicle Lateral ControlUnder Fault In Front And/Or RearSensorsTO4204/MOU384–MasayoshiTomizuka, UCBThis project evaluates the perfor-mance and robustness of the mag-netometer-based lateral control sys-tem when either the front or rear setof magnetometers fails. The projecthas designed, simulated and experi-mentally tested lateral controllers thatutilise only the front set and only therear set of magnetometers. An Au-tonomous Lateral Controller (ALC)that is based on measurements oflateral error and yaw angle relativeto a preceding vehicle is then de-signed to serve as backup system forthe magnetometer-based controller.The ALC is implemented using a

scanning laser radar. Two control-lers have been designeds; one calcu-lates the lateral deviation of the con-trolled vehicle relative to an onlinegenerated trajectory of the preced-ing vehicle based on the measure-ments of the laser radar, and theother utilises the yaw rate sensoralong with the laser radar and theroad curvature. The ALC will be inte-grated with the magnetometer-based lateral controller.

Fault Tolerant Lateral Control ForTransit Buses And TrucksTO4205 –Masayoshi Tomizuka,UCBThis project develops and imple-ments fault tolerant lateral control-lers for transit buses and trucks inpreparation for the PATH Demo2003. The focus is on the design oflateral controllers that are tolerant tolateral controller faults that includethe yaw rate gyroscope, steeringactuator, accelerometer, and mag-netometers. The project will studythe possibility of adding magnetom-eters for better fault tolerant proper-ties. It will explore fault tolerant sen-sor fusion strategies and differentialbraking as a backup system in theevent of a failure in the steeringactuator. The sensor placement de-sign problem of determining thetype, number and location of sen-sors for fault tolerant lateral controlhas been addressed.

Automated Fault TolerantLongitudinal Control Of TransitBusesTO4206–Karl Hedrick, UCBThis project develops and imple-ments fault tolerant longitudinalcontrollers for transit buses in prepa-ration for the PATH Demo 2003. Theproject will develop a realistic modelof a transit bus. This will involve thedevelopment of the mathematicalmodels of the bus subsystems forlongitudinal control. These sub-systems include an engine model, atransmission and wheel dynamicsmodel, and a pneumatic brake sys-tem model. The bus model will besimulated and verified using experi-mental data. A fault detection anddiagnostic system and automatedcontrol laws which provide reliableoperation under both nominal andfaulty operating conditions will bedesigned. The fault tolerant control-lers will be implemented and experi-mentally verified.

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Vehicle Control Experi-ments and Field TestsVehicle Control ExperimentalResearch And SupportTO4227–Dan Empey, UCB/PATHA significant portion of the AVCSSwork at PATH requires experimentalvehicles to support the research,development, testing and validationof the control systems. This projectcontinues the support that the Ve-hicle Control Experimental Groupprovides for ongoing automatedvehicle research work needed by thevarious proposed and continuingprojects at PATH. The group consistsof specialists in control systems, com-munications, electronics, softwaredevelopment and implementation,as well as hardware development,integration and maintenance. Theproject covers general Task Ordersupport, support of the heavy truckprojects, fault-tolerant controls forbuses and trucks, compression brak-ing control, truck emissions and fuelconsumption, integration of vehiclecontrol and communication, inte-gration of GPS/INS and magnets forvehicle control, adaptive cruise con-trol experiments, communicationsystems, testing of fault detectionalgorithms, fault diagnosis for ve-hicle control, and evaluation of lon-gitudinal range and range rate sen-sors. Maintenance and upgradingof the fleet of PATH test vehicles isrequired on a continuing basis, andis also covered under this project.

PATH Demo 2003TO4228–Dan Empey, UCB/PATHThis project is intended to jump-start the Demonstration 2003 ofPATH development of heavy-dutyvehicles. It will first develop the sys-tem requirements, such as actuatorbandwidth and computer input-out-put specifications, of the demo ve-hicles. Vehicle development tasksthat include the development ofsteering actuator and brake actua-tor will be initiated. Lateral and lon-gitudinal control algorithms will beexperimentally tested to verify theirperformance and robustness on anexisting heavy-duty vehicle.

TO4229 — Dan Empey, UCB/PATHCaltrans and PATH plan to conducta large-scale demonstration in 2003to showcase AHS technologies andinnovative Bus Rapid Transit (BRT)and automated freight transport ser-

vices supported by these technolo-gies. The demonstration would in-clude three Class 8 trucks and two40-ft and one 60-ft articulated tran-sit buses, operating in full or semi-automatic modes, and is an impor-tant milestone in the developmentof vehicle highway automation tech-nologies. While there is no doubtthat PATH has the technical capabil-ity of developing the demonstrationsystems for Demo 2002, PATH willlack most of the OEM support andhas to rely on PATH staff and subcon-tractors to develop and install all ofthe required equipment and sub-systems. To support the develop-ment effort, the funding of thisproject will be used to hire addi-tional engineers and technicians, anduse subcontracts for some develop-ment work such as fabrication ofsensor mounts and brackets. Theproject consists of several develop-ment steps: (1) system planning anddesign, (2) vehicle development, (3)control system development, (4)communication system develop-ment, (5) human-machine interfacedevelopment, (6) software develop-ment, (7) maintenance and support,(8) system integration, (9) planningfor the demonstration, (10) improve-ments of PATH facilities, and (11)planning for public relations.

Vehicle SafetyVehicle Braking ControlAdvanced Braking Methods ForLongitudinal Control Of Commer-cial Heavy VehiclesTO4200/MOU372–AnnaStefanopoulou, Univ. of MichiganThis project develops models andanalysis for integration and coordi-nation of advanced compressionbraking methods with conventionalbraking systems for longitudinal con-trol of heavy-duty vehicles. A de-tailed crankangle based diesel en-gine model and a low-order enginetorque model for a Class-8 commer-cial heavy-duty vehicle has beendeveloped. The model is based onenergy conservation principles inaddition to static engine maps pro-vided by the manufacturers, and iscapable of describing the intrinsicinteractions between individual cyl-inder intake and exhaust processes,and turbocharger dynamics duringcombustion and braking modes andthe transition between these modes.Longitudinal control algorithms werealso developed to integrate the com-

pression brake actuator with the ser-vice brakes and gear ratio adjust-ments to accomplish aggressive brak-ing maneuvers and control vehiclespeed during large changes in thegrade. The design technique is basedon the Speed-Gradient approach,whereby a control action is selectedin the maximum descent directionof a scalar function.

Vehicle Safety Assessmentand Safety EnhancementEnhanced AHS Safety ThroughThe Integration Of VehicleControl And CommunicationTO4210–Karl Hedrick, UCBThe project is focused on estimatingand communicating the friction char-acteristics of the road to roadside forperforming safe vehicle controls.There are three main problems: (1)tire/road friction estimation, (2) firstcontact problem of locating a ve-hicle and inter-vehicle communica-tion, and (3) coordinated emergencyvehicle control. Currently, all single-vehicle friction estimation tasks arecompleted. The key estimation algo-rithm is based upon so-called “slipcurves” which are plots of normalisedlongitudinal force versus longitudi-nal slip. For the communication prob-lem (2), two communication archi-tectures have been developed,namely, a Distributed Architectureand an Infrastructure Supported Ar-chitecture. The Infrastructure Sup-ported Architecture requires someroadside infrastructure while the Dis-tributed Architecture realises thenetworking service through the peer-to-peer interaction of vehicles alone.A emergency platoon controller willbe developed, focusing on the im-provements that communicationscan offer, to allow emergency ma-neuvers of a platoon of vehicles.

Safety Performance And Robust-ness Of Heavy Duty VehiclesTO4211/MOU390–ChristianGerdes, StanfordThe purpose of the project is to makerobust claims about the performanceof heavy trucks with AVCSS tech-nologies in safety-critical conditions,with the consideration of the com-plexity of truck model dynamics thathas made it difficult to establish whatconstitutes a safe truck. A list of me-chanical properties has been com-piled for heavy truck componentssuch as tries and suspension. Tireproperties include cornering stiffnessand longitudinal stiffness. Suspen-

Trucks to be used in Demo 2003

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sion properties include roll stiffness,roll center height, and lateral stiff-ness. A literature review has beencompleted to catalog variations inparameter values. This provides abasis for developing models withphysically realistic parameter values.It has also gathered information con-cerning the possible variations inphysical parameters such as configu-ration and loading. A set of metricsto quantity safety measures for heavytrucks has been established. Someof the more common measures in-clude braking efficiency, friction de-mand, static rollover threshold, andload transfer ratio. Using a dynamicmodel, sensitivity analysis has beenperformed to determine which para-metric variations produce the mostsignificant impact on the safetymetrics. A model of a heavy truckwith greater level of kinematic anddynamic fidelity than previouslyavailable at PATH has been devel-oped. This is built using commercialmulti-body dynamics software inorder to reflect the state-of-the-artcurrently available in industry. Ex-perimental validation of the multi-body truck model is underway. Workhas also started in energy-based re-duction techniques of the model.

Detection And Avoidance OfCollisions: The Assessment OfCollision Threat (ACT) ModelTO4220–George Andersen, UCRThe project investigates the visualinformation (such as angle of colli-sion) used by drivers to detect andavoid collisions. Failure to detect andavoid collisions can be the result ofa number of factors including exces-sive speed, vehicle malfunction, orhazardous road conditions. How-ever, a central factor in all of thesefactors is the ability of the driver tocorrectly perceive, attend to, andavoid potential collisions. Psycho-physical experiments using a drivingsimulator are conducted to derivethe relevant model parameters of anAssessment of Collision Threat (ACT)model. The ACT model will then beevaluated in different driving sce-narios, and microsimulations ofdriver’s perception of threat of im-pending collisions will be developed.The research focuses on understand-ing the perceptual and attentionallimits of driver information for colli-sions. It includes examination of vi-sual and attentional factors that leadto decreased accuracy in threat as-sessment by drivers.

Safety Assessment Of AdvancedVehicle Control And SafetySystems (AVCSS): A Case StudyTO4225–Wei-Bin Zhang, Ching-Yao Chan, UCB/PATHThis project continues the collabo-ration between PATH and INRETS inFrance in performing safety analysisand evaluation of advanced vehiclecontrol and safety systems (AVCSS)such as vehicle longitudinal and lat-eral control systems, so that errorsin the process of specification, de-sign, development and integrationcan be revealed prior to the imple-mentation of the new technologiesand hazardous consequences can beprevented. PATH contributes exper-tise in vehicle control and failureanalysis to identify, analyse and clas-sify the risks inherent in each part ofan AVCSS system. INRETS providesexpertise in safety analysis and assess-ment. The project also considers sen-sor reliability and diagnosis, and de-velop a system architecture to in-clude fault tolerance and fault detec-tion. As a case study, a transit bus isused as a study platform. The nextemphasis is on evaluation of collisionwarning system sensors and devel-opment of safety verification and cer-tification methods to apply to Demo2003.

Fault Diagnosis andManagementDevelopment And Implementa-tion Of A Vehicle-Centered FaultDiagnostic And ManagementSystem For The Extended Path-AHS ArchitectureTO4207/MOU373–MasayoshiTomizuka, Roberto Horowitz,Karl Hedrick, UCBThis project develops and implementsa comprehensive fault diagnostic andmanagement system for the ex-tended PATH-AHS architecture de-signed for fault tolerant lateral andlongitudinal control systems. Faulttolerant lateral controllers and faultdiagnostics for the lateral control sys-tem, and the detection and process-ing of the multiple faults in the longi-tudinal control system have beendeveloped. The fault tolerant lateralcontrol scheme will be integratedinto the existing fault managementscheme. The overall hierarchical struc-ture consisting of the health signals,fault tolerant controllers and the faultdetection and identification systemwill be completed in the final phaseof the project. Implementation and

experimental testing of the com-bined fault diagnostic and manage-ment system will also be completed.

Development Of IntegratedMeso/Microscale TrafficSimulation Software For TestingFault Detection And Handling InAHSTO4208/MOU383 –RobertoHorowitz, UCBThis project develops an integratedmeso-scale and micro-scale simula-tion package for efficient simulationof a large scale AHS at the physical,regulation, coordination and link lay-ers. The simulation provides infor-mation on the impact of the AHStechnologies on system safety andcapacity. It studies and evaluates howfaults in a vehicle impact the overallAHS performance and capacity, howthe roadside control systems can re-act to faults and perform degraded-mode activities, and how the road-side control system can detect faultseither in the vehicle or in its owninfrastructure. The existing SmartAHSframework was extended to simplifyand improve communication sys-tem simulations, incorporate linklayer control and improve simula-tion speed. The meso-scale SmartCAPand micro-scale SmartAHS simula-tion programs are integrated to in-clude link layer capability and im-prove the performance of the coor-dination and regulation layer simu-lations.

Testing And Evaluation OfRobust Fault Detection AndIdentification For A FaultTolerant Automated HighwaySystemTO4209–Jason Speyer, UCLAThis project performs experimentalimplementation and verification offault detection and identification al-gorithms developed under perviousprojects. The fault monitoring sys-tems detect and identify failures inany actuator or sensor onboard thePATH Buick LeSabre test vehicles. Arobust fault monitoring system hasbeen implemented. It has been testedand fine tuned using nonlinear simu-lation. It works well when the vehicletravels at both constant and variablespeeds. The system will also be evalu-ated using empirical vehicle data.The fault monitoring system will bewritten in C code and evaluated inreal-time on a laptop connected tothe computer onboard a PATH testvehicle.

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Enabling TechnologiesAdvanced Vehicle LocationIntegration Of GPS/INS AndMagnetic Markers For AdvancedVehicle ControlTO4213/MOU391–Jay Farrell,Matthew Barth, UCRThis project designs, develops andevaluates the robustness of a vehiclepositioning system by integratingthe magnetometer system devel-oped at PATH with a GPS/INS systemdeveloped under a previous projectto achieve the performance and reli-ability necessary for automated ve-hicle control. The integrated systemfuses information from the magne-tometer and GPS/INS systems to re-liably maintain the vehicle controlstate. The fusion algorithm is de-rived using optimal estimation meth-ods, and C codes has been imple-mented. MATLAB-based obser-vability and covariance analysis arealso performed to determine thesoundness of the integrated sensingsystem for various combinations ofthe available sensors. The scope in-cludes design, analysis, implemen-tation and evaluation of the inte-grated system. In addition, the sys-tem is designed to achieve the in-crease reliability necessary for suc-cessful commercialisation. As a finaldeliverable, a demonstration ofclosed loop vehicle control based ondata from the integrated system willbe performed on a PATH vehicle.

Communication SystemsA Robust Communication Link AndArchitecture Design For The AHSTO4212/MOU389–AndreaGoldsmith, StanfordThis project investigates the differ-ent communication requirementsand quality of service (such as mes-sages of varying lengths and priori-ties) for data access in AHS commu-nications. It designs robust commu-nication link and data access proto-cols by considering the problem thatthe overall communication architec-ture for an AHS is complicated by (i)the propagation environment of thesignals, (ii) the existence of multipleinterference signals, and (iii) themobility and dynamic character ofplatoons. The time-varying propa-gations of the signals between ve-hicles, between platoons, and fromplatoons to roadway infrastructurehave been characterised. Commer-cial LANs and their performance have

also been investigated. The impactof packet loss and delay on the stringstability of platoons has also beenstudied. The research is now focusedon ensuring the robustness of thecommunications link and channelaccess given the propagation envi-ronment and the potential interfer-ence signals. This will be accom-plished by investigating the perfor-mance of the platoon control proto-cols under packet delays and loss.

Path LaboratoryTO4224–Raja Sengupta, Chin-Woo Tan, UCB/PATHThis project includes two activitiesled by two principal researchers, oneon navigation and one on wirelesscommunication. The navigation ac-tivity involves developing signal pro-cessing algorithms for a gyroscope-free inertial navigation system andintegrating it with a GPS system in anew way so that the errors are re-duced compared to other alterna-tives previously developed. The wire-less communication activity extendsthe work on vehicle-vehicle commu-nication protocols to vehicle-road-side protocols and wireless roadsideinfrastructure, with particular rel-evance to the current national Dedi-cated Short Range Communication(DSRC) standardisation efforts, inwhich PATH has become an impor-tant participant representing themore advanced safety applications.The vehicle-vehicle communicationresearch is continued in support ofthe needs of Demo 2003.

Human Driver ModelsHuman Driver Model DevelopmentTO4222–Delphine Delorme, UCB/PATHThis project continues and extendsthe effort on human driver model-ling development that started undera previous PATH project. The goal isto provide other researchers with atool for analysing the effects of ITSsystems on conventional driving per-formance in terms of throughput byreproducing the information pro-cessing string developed by thedriver. The project has extended andrefined the capabilities of the humandriver model by developing moreprocessing mechanisms that assessthe effectiveness of other drivingassistance systems. The next focuson the model refinement is to repre-sent them in forms that are suitablefor computer simulation, with a plan

to implement the models with theSmartAHS structure. The project alsoincreases the number of driving pa-rameters that the human drivermodel should incorporate, and vali-dates the model using data collectedduring real driving of a test vehiclebeing developed under TO 4223.

Development Of A Vehicle DataAcquisition System For Naturalis-tic Driving Data CollectionTO4223 –Scott Johnston, UCB/PATHIn this project, a vehicle data acqui-sition system (DAS) is being devel-oped to collect data about how hu-man drivers actually drive. The datawill be used to help calibrate andvalidate the human driver modelthat is being developed under TaskOrder 4222. The DAS is designed tobe unobtrusive to the driver of thetest vehicle and drivers of other ve-hicles. It is capable of recording manydriving parameters such as throttleposition, acceleration, longitude andlatitude, range rate, and presence ofadjacent vehicles. Under this project,the needed components for the DASare purchased, and data collectionand analysis software are developedand refined, and they will be inte-grated on a late model passenger caron loan from Caltrans.

Human-MachineInteractionsAutomated-Manual Transitions:Human Capabilities AndAdaptive Cruise ControlTO 4221–Theodore Cohn, UCBThis project deals with automated-to-manual transition of an ACC ve-hicle when the vehicle in front sud-denly applies maximum braking. Itdevelops experiments using a driv-ing simulator to investigate a humanoperator’s ability to detect the clos-ing intervehicle spacing and the timeto collision. The driver examines thevisual information and determinesthe need to assume manual control.A literature review of how humansjudge headway and its change iscompleted. Person-in-the-loopmicrosimulation apparatus has beendeveloped. Simulation studies of thehuman detection of headway reduc-tion following abrupt braking by alead vehicle will soon begin. A seriesof studies that examines which ofthe available cues is used by thehuman observer to detect gap orheadway reduction will also be con-

GPS/INS and Magnetic Markers

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ducted. Based on the data, a modulewill be developed and appended tothe PATH’s Human Driver Modelwhich predicts human behaviour inhe scenarios studied in this project.

AerodynamicsThe Aerodynamics Of Heavy TrucksTO4214/MOU387 –Fred Browand,USCThis project focuses on two impor-tant aerodynamic components forheavy-duty vehicles. The first task isto carry out wind tunnel measure-ments of drag and potential fuelsavings for two scale-model tractor-trailers in tandem at short headway.The second task is to derive sufficientvehicle roll stability margin for safehandling of Class 8 trucks at highspeeds and under strong cross-windand abnormal road conditions (suchas a wet highway). The measure-ments are made on static tractor-trailer configurations, and yield esti-mates of the quasi-steady limit forces.The wind tunnel experiment de-scribes 6-component force and mo-ment data measured for both thecab and the trailer of a simplifiedmodel truck. The results show thattwo trucks in tandem always presentless drag than the same two trucksoperated in isolation. The saving indrag depends upon the value of thetruck drag coefficient in isolation.The measurements employ not justa single truck shape, but a variety ofsimple truck shapes.

Real System DeploymentAnalyses Of The Response OfPavements Containing Plugs ForVehicle GuidanceTO4219–Carl Monismith, UCBThis project examines the influenceof magnets on pavement perfor-mance, especially cracking, by con-sidering the effects of traffic loadingand temperature changes through aseries of pavement simulations ofrepresentative pavement structureswith magnets currently in use. Analy-ses are performed using differentsensor sizes and placement withinthe pavement structure. The initialphase of the project is devoted to theanalyses of pavements containingmagnets of different configurations.Three-dimensional finite-elementidealisations of the selective pave-ment structures and sensor sizes andlocations are being developed. Traf-fic is limited to representative truckaxles and associated legal axle loads.The stresses applied by the tires in-

clude both longitudinal and trans-verse shear as well as normal stresses.The effects of rate of loading (truckspeed) will be evaluated. A range oftemperature conditions will also beexamined.

Refinement Of Magnetic Refer-ence/Sensing System In Prepara-tion For CommercializationTO4226–Ching-Yao Chan, UCB/PATHThis project explores several criticalissues with regard to the magneticmarker positioning system, so that itcan be commercialised and used inreal system deployments. The issuesto be researched include: (1) Themeasurement of background mag-netic fields at various roadway sites.(2) The comparison of magneticmarkers and magnetic tape providedby 3M. (3) The testing of alternativemagnetic sensors. (4) Theoptimisation of a complete mag-netic reference/sensing system. (5)The development of a standard cod-ing scheme for magnetic marker in-stallation. (6) The development ofroadmap and opportunities for earlyimplementation of PATH lateral con-trol technologies.

Emissions ModelsDevelopment Of A Heavy-DutyDiesel Modal Emissions And FuelConsumption Module For SmartAHSTO4215–Matthew Barth, UCRThis project develops and verifiesmodels for emissions from heavy-duty diesel engines. Heavy-duty ve-hicle modal emission models havenot yet been developed to data pri-marily due to the lack of appropriatesecond-by-second emissions data.Under a project sponsored by theU.S. EPA, an emission trailer is beingdeveloped to measure instantaneousemissions. Using the measured emis-sions data, an emissions model willbe developed and verified. The de-sign of a heavy-duty diesel emissionsmodel architecture is well under-way. As an initial design for the archi-tecture, the original comprehensivemodal emissions model architecturefor light-duty vehicles is used. Thisarchitecture is modified to includethe differences in some of the keymodules and associated analyticalequations. Once the model is rea-sonably complete, it will be inte-grated with PATH’s ITS simulationtools (such as SmartAHS) and usedto evaluate numerous automation

scenarios that can involve passengercars, buses, and trucks. The emis-sions model will also be combinedwith USC’s automatic control sys-tem simulation tools to evaluate vari-ous ITS scenarios such as intelligentcruise control.

System OperationsAHS DeploymentThe AHS/Street Interface EffectsOf Capacity Concentrations OnSystem PerformanceTO4216/MOU386 –RandolphHall, USCAutomated highways offer the po-tential to increase throughput onhighways. But in order for such im-provements to be effective at reduc-ing total trip travel time, it must bepossible to absorb these increases inthroughput on the streets that inter-face with the AHS. This project de-signs AHS/street interface to accom-modate the high volume of AHStraffic that would occur in the vicin-ity of AHS access/egress points. Thestudy provides guidance to deter-mine: (i) proper spacing betweeninterchanges, (ii) traffic control strat-egies to prevent queue backup ontothe mainline, (iii) localised street im-provements to accommodate flows,and (iv) upper bounds on sustain-able highway traffic flows, account-ing for street bottlenecks. The projecthas three principle tasks: (i) strategicmodelling, (ii) operational model-ling, and (iii) site specific analysis.Work is underway on the effects ofentrances and exits on platoon for-mation and dispersion. Specifically,the research examines the effective-ness of sorting vehicles into destina-tion groups, with respect to queu-ing, entrance/exit design and high-way throughput. Both analytical andsimulation models have been cre-ated. Analysis of specific exit/en-trance locations is also underway. AGIS database has been developedfor a set of urban freeways, includingdemographic characteristics of sur-rounding zones, and characteristicsof the freeways. This has been cre-ated in the ArcView environment.

Evaluation Of The Effects OfIntelligent Cruise ControlVehicles In Mixed TrafficTO4217/MOU392–PetrosIoannou, USCThis project conducts experimentsusing actual vehicles to evaluate theeffects of Intelligent Cruise Control(ICC) vehicles in mixed traffic. It was

Refinement of Magnetic Reference/Sensing System

Aerodynamics of Heavy Trucks

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shown in MOU317 that the pres-ence of ICC vehicles in traffic flowimproves traffic flow characteristics,air pollution levels and fuel efficiency.The ICC vehicles do not contributeto the slinky-type effects observed inmanual traffic due to its accurateposition and speed tracking. Thesmooth response of ICC vehicles fil-ters traffic disturbances and signifi-cantly reduces fuel consumption andlevels of pollutants during situationswhen the lead manual vehicles per-form rapid acceleration maneuvers.This has been demonstrated usingvalidated car following and ICCmodels. The results of the experi-ments will then be used to study theeffects of ICC vehicles on the macro-scopic behaviour of mixed traffic.Issues such as stability of traffic flowand attenuation of shock waves duesto the presence of ICC vehicles inmixed traffic will be analysed.

Conceptual Development AndPerformance Assessment For TheDeployment Staging Of Ad-vanced Vehicle Control AndSafety SystemsTO4230–Mark Miller, UCB/PATHThis project represents a bridge be-tween PATH research that is nearingcompletion (MOU 366) and Demo2003. MOU 366, in its investigationof deployment staging leading toautomated highway systems, hasmodeled the effects of driver con-trol assistance systems relative tohuman driving, including both au-tonomous and cooperative cruisecontrol systems, evaluated the ef-fects of such systems on highwaytraffic flow capacity, and examinedinstitutional issues. The proposedwork will focus on three areas of in-vestigation: 1. Evaluation of the ef-fects of driver control assistance sys-tems relative to human driving forthe multilane highway case withlight duty passenger vehicles, 2.Conceptual development for similarand eventual modeling and evalua-tion of trucks and buses, and 3. Re-view of the state of international re-search (including simulation andevaluation) and technology demon-strations of vehicle-highway automa-tion systems. These three tasks willhelp fill the gaps in knowledge aboutdeployment staging toward coop-erative vehicle-highway automatedsystems and provide a more com-plete picture at Demo 2003.

Bus Rapid TransitDefinition And Evaluation OfBus And Truck AutomationOperations ConceptsTO4218–Jacob Tsao, Jan Botha,San Jose State Univ.The project develops and evaluatesoperating concepts for a fully auto-mated bus-truck AHS, and the im-mediate steps that will facilitate thedevelopment of such AHS. Operat-ing concepts are developed and somebenefit-cost elements are then iden-tified for a more detailed benefit-cost analysis in the future. The focusis one those major cost-benefit ele-ments that differ significantly amongthe alternatives. Operating conceptswill be evaluated for transportationcorridors only. This project comparessome aspects of the implementationof a bus-AHS to their counterparts ofan existing light-rail system in Cali-fornia; it also compares a bus-AHS toa conventional busway with respectto similar aspects. The conventionalfreight-transportation alternativesinclude addition of a conventionallane, addition of a truck lane, addi-tion of an exclusive AHS truck lane,and intermodal rail.

Heavy-Duty Diesel ModalEmissions and Fuel ConsumptionModule

Response of Pavements ContainingPlugs

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PATH’s MobileOffshore Base (MOB)project, developedfor the US Office ofNaval Research,consists of threetwo-meter-longmodules, each ofwhich emulates asemi-submersiblevessel the length ofan aircraft carrier.

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Mobile Offshore Base (MOB)Karl Hedrick, William Webster – UCBUsing cooperative vehicle controltechnology, integrating communi-cations and hybrid control, develop,test and demonstrate a control sys-tem for “dynamic positioning” ofsemi-submersible vehicles. Thisproject for the Office of Naval Re-search has led to a scale-model test,in the towing tank at UCB/RFS, ofthe MOB vehicles, showing that theycan be “platooned” accuratelyenough to produce a virtual runwayat sea for the landing of large trans-port aircraft.

Model-Based Integration of Em-bedded Software (MoBIES)Pravin Varaiya, Karl Hedrick – UCBWith funding from the Defense Ad-vanced Research Projects Agency(DARPA), PATH is supporting thisprogram to facilitate the transitionof real-time control system designsfrom the current state of practice ofmultiple analysis, simulation, cod-ing and test environments to thetarget of model-based end-to-endreal time implementations withminimum effort and maximum ac-curacy. PATH vehicles are beingequipped to serve as the test bedsfor the automotive sample prob-lems in vehicle-vehicle communica-tion, focusing on “cooperative”adaptive cruise control with someforward collision avoidance func-tionality as well.

Distributed Autonomous AgentNetworksRaja Sengupta (Project Manager)– UCB/PATHThis project is developing wirelessad-hoc networking and service net-working technologies for the coop-erative operation of unmanned airand ground vehicles, under thesponsorship of the Office of NavalResearch (ONR). The project is alsodeveloping a theory of networkedcontrol, i.e., multi-vehicle controlthat is robust to the uncertaintiesinherent in wireless data communi-cations.

A Rural Field Test of the RoadViewSystemDan Empey (Project Manager) –PATHThe lane guidance assistance sys-tem developed for the AdvancedSnowplow Project is being tested inwinter operations in both Californiaand Arizona to collect data regard-ing its use by drivers and how it

helps them drive better in poor vis-ibility conditions.

Development of the Advanced Ro-tary Plow for Snow Removal Op-erationsDan Empey (Project Manager) –PATHA large rotary snow blower is beingequipped with the PATH magneticguidance sensing system and a steer-ing actuator so that it can be steeredautomatically for low-speed opera-tion on California highways, whereit is used to clear heavy snow accu-mulations close to the guard rails.The automatic steering system isintended to avoid the damage thatis currently incurred by guard railswhen drivers use them for mechani-cal guidance in poor visibility condi-tions.

Railroad Grade Crossing SafetyT. Cohn – UCB, Jim Misener –PATHDescription: This is a laboratoryand field investigation of whatcauses grade crossing crashes alongthe San Joaquin corridor from twopoints of view, driver perceptionand driver cognition. The percep-tion investigation consists of an in-vestigation of incandescent signalsvs. LED, both in the laboratory andin the field. The cognition investi-gation consists of equipping aCaltrans-owned Amtrak locomotivewith surveillance cameras to under-stand, then model, behaviors of driv-ers that immediately precede gradecrossing incursions.

SmartCruise 21 Demo 2000Han-Shue Tan (Project Manager)– PATHPATH was one of only three non-Japanese participants invited todemonstrate vehicles at theSmartCruise 21 Demo 2000 inTsukuba City. The Buick test vehiclewas used to compare magnetic sens-ing performance of the originalPATH system and a new sensor con-figuration from a Japanese supplier,and to show how we could use themagnetic marker infrastructure in-stalled in the Japanese test track,even though it is significantly differ-ent from our magnetic markers. Thedemonstration included driving thetest vehicle around the 6 km testtrack and a tunnel filled with fogunder a combination of lateral con-trol modes – driver assisted by agraphical display based on that de-veloped originally for snowplowguidance, lane departure warning,

OUTSIDE FUNDED PROJECTS

lane departure prevention and com-pletely automatic steering. Perfor-mance data were recorded for all ofthese conditions over a wide rangeof speeds and roadway conditions,and with frequent switching amongcontrol modes.

Transit Bus Forward Collision Warn-ing System Requirements Defini-tionWei-Bin Zhang (Project Manager)– PATHThe operating environment for ur-ban transit buses is much more com-plicated than the highway environ-ment for which commercial colli-sion warning systems are designed.This Intelligent Vehicle Initiative (IVI)project involves instrumenting aSamtrans (San Mateo County Tran-sit Authority) bus with multiple sen-sors to develop a comprehensivecharacterization of its operatingenvironment, and then using theextensive data gathered using thosesensors to support development ofprototype collision warning soft-ware, which can serve as the basisfor defining the performance re-quirements for a deployable sys-tem.

Transit Bus Rear Collision Warn-ing SystemT. Cohn – UCBProf. Theodore Cohn is supportingthe development of a rear collisionwarning system for transit busesunder the IVI program by testingthe effectiveness of alternative con-figurations of warning lights in-tended to be mounted to the backof a bus belonging to the Ann ArborTransit Authority.

Automotive Collision AvoidanceSystem (ACAS)Steve Shladover, Jim Misener –PATHPATH has developed a threat-as-sessment simulation system to beused by researchers at General Mo-tors and Delphi Automotive to sup-port their development of the ACASwarning algorithms. This softwareis built on the foundation of existingSHIFT and SmartAHS simulationsoftware, but includes implementa-tion of a variety of new modules torepresent alternative sensor charac-teristics and hazard environments,together with graphical animationand integration of sensor data withvideo imagery of the driving scene.

Rotary Snowblower

Railroad Grade Crossing Safety

Rural Snowplow Testing

SmartCruise 2000, Japan

PATH Research

24

Identification of Drivers Under theInfluenceScott Johnston (Project Manager)– PATHUnder funding from the CaliforniaOffice of Traffic Safety, PATH is ex-ploring the feasibility of automaticscreening of special-purpose trafficsurveillance camera images to iden-tify vehicles whose erratic move-ments may indicate an increaseprobability of drivers who are underthe influence of alcohol or drugs.When such erratic movements aredetected by the image processingsystem, officers stationed down-stream on the bridge or highwaywould then be alerted to look outfor a vehicle fitting the descriptionof the one that was moving errati-cally.

Collision Recording and Docu-mentationChing-Yao Chan (Project Man-ager) – PATHDescription: This project, underthe sponsorship of the CaliforniaOffice of Traffic Safety, is exploringhow ITS technology can be used toexpedite the process of collisiondocumentation and analysis to re-duce the working hazards (for High-way Patrol officers) and the laneclosure times (for the public) asso-ciated with post-crash reporting.Efforts are concentrating on devel-opment of hardware and softwareto facilitate surveying and docu-menting the collision scene.

The Use of Combined Physical andSituational Models for Data Fusionin ACC SystemsKarl Hedrick – UCB/PATHAdaptive Cruise Control (ACC) sys-tems need to be able to adjust theirperformance to address a wide va-riety of traffic conditions, especiallyif they are to be usable in stop-and-go traffic. In this project, we ex-plore how to use the data alreadyavailable from the forward-lookingradar of the ACC system, combinedwith vehicle inertial sensors, GPSand a map database, to character-ize the driving environment, as wellas to diagnose sensor faults. Fol-lowing analysis and simulationstages, the proposed data fusionapproach is to be tested on an ACCvehicle provided by the industrialsponsor of the project.

The Development of an InertialMeasurement Unit and aHuman-Machine Interface forMotorcycle Navigation SystemsKarl Hedrick – UCB/PATHThis project designs, develops andevaluates an integrated InertialMeasurement Unit (IMU) and Hu-man-Machine Interface (HMI) pro-totype system for motorcycle navi-gation. The IMU will provide unin-terrupted motorcycle state infor-mation. The HMI is aimed at provid-ing navigation information to thedriver so that the perceptual andcognitive demands are safe andconvenient for motorcycle riding.

Development of SmartBRTJim Misener – PATHSmartBRT simulates the operationof a Bus Rapid Transit (BRT) systemand evaluates operation parametersand system performance measures.This will allow user-defined BRT con-cepts to be evaluated. The core ofSmart BRT is a microsimulation,complete with appropriate bus andinfrastructure geometric librariesand high-fidelity photo-realistic 3Dgraphics. This will allow computa-tion and visualization of the incre-mental effect of adding ITS tech-nologies to bus rapid transit opera-tion, but without the high capitalinvestment of field tests.

Research to Support the Deploy-ment of Bus Rapid Transit (BRT)SystemsWei-Bin Zhang – PATHPATH has initiated a cluster of newresearch projects to help supportthe development and deploymentof Bus Rapid Transit (BRT) systems.These include development of anadaptive bus signal priority controlsystem, precision docking, an ad-vanced bus stop with high-accu-racy traveler information, and as-sessment of the institutional chal-lenges and opportunities associatedwith BRT. This work brings to-gether AVCSS and ATMIS research-ers in PATH, together with new part-ners in the Caltrans Division of MassTransportation, the Santa Clara Val-ley Transportation Authority and theFTA-sponsored BRT Consortium.

Evaluation of Sensor-Friendly Ve-hicle and Roadway SystemsJim Misener – PATHThis is a preliminary evaluation ofthe opportunities to facilitate targetdetection and discrimination by thesensors used in automotive collisionwarning and control assistance sys-

tems. Under funding from theUSDOT IVI Program, subcontractedthrough Bechtel, PATH researchershave studied the feasibility of “tag-ging” and “masking” vehicles androadway infrastructure elements sothat they are more recognizable byin-vehicle sensors, making possiblesimpler and more effective signalprocessing. Some experiments ona few promising candidate tech-nologies were followed by a pre-liminary assessment of the benefitsthat could be gained from use ofthese technologies.

PATH Research

25

At Demo 2000, PATH showed how a

magnetic marker guidance system can be

used to provide drivers with a guidance

display to help steer their vehicles

accurately. PATH also demonstrated a

new feature that lets drivers switch

automatic steering on and off. The

Japanese implementation of magnetic

marker technology differed from PATH’s

implementations in the United States in a

number of important ways. See

www.path.berkeley.edu on the web for

the full story.

Demo 2000

26

PATH Publications

26

PATH Publications

27

ATMS (Advanced TransportionManagement Systems)

Automated Travel Time Measure-ment Using Vehicle Lengths FromLoop Detector Speed TrapsBenjamin Coifman, Michael CassidyPresents a vehicle reidentificationalgorithm for consecutive detectorstations on a freeway. In this meth-odology, a vehicle measurementmade at a downstream detectorstation is matched with thevehicle’s corresponding measure-ment at an upstream station. Thealgorithm is intended to improvefreeway surveillance by measuringthe actual vehicle travel times, thusmaking it possible to quantify con-ditions between widely spaced de-tector stations.UCB-ITS-PRR-2000-12*August 2000, 76 pages, $15

Database Environment for FastReal-time Simulation of UrbanTraffic Networks with ATMISR. Jayakrishnan, Phillip Sheu,Taehyung Wang, Min-Hua XuDescribes a project that developedthe environment for using theDYNASMART simulation modelwith accompanying graphical userinterface (GUI) for real-time trafficsimulation and scenario analysiswith feedback from a real urbannetwork. A database managementsystem to handle data for multipleprocesses during parallel simula-tion was designed to complete theenvironment for simulation-basedanalysis of Advanced Traffic Man-agement and Information Systems(ATMIS) in real-time at theCaltrans/PATH Testbed at UCIrvine.UCB-ITS-PWP-2000-4*March 2000, 52 pages, $15

Determining the Capacity Benefitsof Real-time Signal Control atIntersectionsAlexander Skabardonis, Brian R.Gallagher, Kartik P. PatelTraffic responsive control strategiesare increasingly being imple-mented to improve intersectionperformance. Critical intersectioncontrol (CIC) is using real-timetraffic data to better assign greentimes to conflicting movements.However, the benefits of CIC havenot been assessed. The effective-ness of CIC was evaluated at seven

PATH’s Berkeley Highway

Lab boasts 14 video

cameras that perch atop

an Emeryville building

skirting Highway 80 and

afford spectacular vistas

that range from

Richmond to the San

Francisco Bay Bridge

approach and the

Oakland maze. These

eyes in the sky collect

traffic pattern data for

research and monitoring

purposes, and to be used

as ground truth for

information caught by

loop detectors imbedded

in the roadway below.

Berkeley Highway lab’s

website

signalized intersections in the Cityof Los Angeles. Findings indicatethat CIC generally improves trafficoperations.UCB-ITS-PWP-2000-25*December 2000, 18 pages, $5

Dynamic Origin/Destination Esti-mation Using True Section Densi-tiesCarlos Sun, Himanshu PorwalDemonstrates the feasibility ofanalyzing the potential benefits ofusing section density as a measurefor estimating dynamic origin/destination demands. Simulationsare performed using networkand demand levels that arebased on the Caltrans/PATHATMIS testbed at UC Irvine. Twotraffic assignment schemes werestudied: one based on simula-tion (DYNASMART) and the sec-ond based on the DTA analyticscheme. Kalman filtering andLeast Squares optimizationmethodologies were used tominimize the errors between thepredicted and the true sectionmeasures.UCB-ITS-PRR-2000-5*March 2000, 148 pages, $20

Experimental Characterization ofMulti-lane Freeway Traffic Up-stream of an Off-ramp Bottle-neckJuan Carlos Muñoz, CarlosDaganzoDescribes field observations ofmulti-lane freeway traffic upstreamfor an over saturated off-ramp, us-ing data from the I-880 freewaynear Oakland, California. Two di-agnostic tools reveal hidden fea-tures of the traffic stream.Concludes with an assessment ofthe vehicle-hours of delay causedby the bottleneck, and proposescongestion mitigation strategies.UCB-ITS-PWP-2000-13*August 2000, 63 pages, $15

Incident Dispatching, Clearanceand DelayRandolph W. HallFocuses on response and dis-patch time of incident crews, andthe effect these variables have oncongestion and delay. The au-thors model response times anddelays for highway incidents, ac-counting for spacing between in-terchanges and the time penaltyfor changing directions, enablinga response vehicle to reach an in-

cident on the opposite side of thehighway. The report demon-strates that any reasonably robustdispatch strategy must take intoconsideration the trade-off ofgreater certainty in response timeagainst stability at higher utiliza-tion levels.UCB-ITS-PWP-2000-14August 2000, 7 pages, $5

INCISIM: Users’ ManualHeng Liu, Randolph HallINCISIM is a computer programthat simulates the occurrence ofhighway incidents, the dispatch-ing of emergency vehicles, and thetraffic flow on the network. Theprogram can represent multipletypes of emergency vehicles. Inci-dents are represented by type clas-sifications and profiles. Delay is cal-culated as a function of these vari-ables, along with traffic flows andhighway capacities. INCISIM pro-duces a complete log of incidentsthat occurred during the simula-tion along with statistics of high-way delays.UCB-ITS-PWP-2000-15*August 2000, 4 pages, $10

Investigation in the Use of Induc-tive Loop Signatures for VehicleClassificationCarlos SunPresents an advanced traffic sur-veillance technique that is basedon pattern recognition and the useof current inductive loop technol-ogy. The feasibility of using loopsignatures for obtaining vehicleclassification information on a net-work-wide level was studied usingdifferent pattern recognition tech-niques, such as classical decisiontheoretic approach and advancedneural networks. Classificationrates of greater than 80 percentwere obtained.UCB-ITS-PRR-2000-4*March 2000, 38 pages, $20

Methodology for Developing aTraffic Surveillance InvestmentProgram: An Application toCaltrans District 4Joy DahlgrenThe complicated decision struc-ture for deciding where and whento install traffic surveillance andwhat type of surveillance to installis broken down into a series ofsteps: identifying informationneeds, determining which can bemet by traffic surveillance, setting

Recent PATH PublicationsResearch Reports, Working Papers, and Technical Notes from January 1-December 31, 2000 are listed below.Those marked with an asterisk can be found on the Web at http://www.path.berkeley.edu/PATH/Publications

dvancedrafficanagementnformationystems

ATMIS

http://www.cs.berkeley.edu/~zephyr/freeway/

will tell you more.

28

PATH Publications

scatter, whenever an experimentencompasses a rush hour withtransitions in and out of conges-tion, some outlying data stub-bornly remain beneath the “equi-librium” curve. The existence ofthese non-equilibrium points is anill-understood phenomenon thatappears to contradict the simplekinematic wave (KW) model oftraffic flow. This paper provides atentative explanation of the phe-nomenon, based on experimentalevidence.UCB-ITS-PWP-2000-24*November 2000, 7 pages, $10

Study of Freeway Traffic Near anOff-RampMichael J. Cassidy, Shadi B. Anani,John M. HaigwoodShows that a disruptive freewaybottleneck can be averted by keep-ing an off-ramp from becomingover-saturated and spilling over tothe exit lane. This is achieved bychanging the logic of a nearby traf-fic signal. This then leads to higherflows being sustained on the free-way segment and preventingbottlenecks from occurring.UCB-ITS-PWP-2000-10*August 2000, 4 pages, $5

Travel Time Estimation on the SanFrancisco Bay Area Network UsingCellular Phones as ProbesJean-Luc Ygnace, Chris Drane,Y.B.Youngbin Yim, Renaud deLacvivierDiscusses the associated institu-tional environment in which cellphones are used, followed by a re-view of cellular positioning tech-niques, reports on results fromanalytical and simulation models,and concludes with a discussionregarding how a field trial could beimplemented.UCB-ITS-PWP-2000-18*September 2000, 4 pages, $15

ATIS (Advanced Traveler Informa-tion Systems)

Evaluation of TravInfo Field Op-erational Test: Final ReportY.B.Youngbin Yim, Mark A. MillerTravInfo is a regional traveler infor-mation system in operation in theSan Francisco Bay Area. TravInfodiffers from other advanced trav-eler information systems (ATIS) inthat the program was organiza-tionally structured as a public/pri-vate partnership, and it featuredan open architecture which pro-vided a database that was acces-sible to all information service pro-viders. This report focuses onevaluations of the institutional re-

criteria for and evaluating the ben-efits of surveillance in various loca-tions, identifying alternative sur-veillance methods and estimatingtheir capabilities and costs, com-paring the ratios of benefits tocosts, and finally matching cost-effective investments with avail-able funds.UCB-ITS-PWP-2000-23*November 2000, 5 pages, $5

New Aggregation Strategies toImprove Velocity Estimation FromSingle Loop DetectorsBenjamin Coifman, Zu-Hsu LeePresents a new approach, usingaggregation methodology, to esti-mate velocity and reduce the im-pact of long vehicles in the origi-nal traffic measurements. The au-thors first present a review of thestate of the practice and the re-lated shortcomings of parameterestimation from single loop detec-tors. This is followed by a descrip-tion of the proposed alternativemethod for estimating velocity.The report concludes by contrast-ing the new approach with con-ventional estimates.UCB-ITS-PWP-2000-12*August 2000, 7 pages, $5

New Methodology for EvaluatingIncident Detection AlgorithmsKarl Petty, Michael Ostland, Jaim-young Kwon, John Rice, Peter J. BickelThe new approach is a cost benefitanalysis where cost mimics the realcosts of implementing an algorithmand benefit is in terms of reductionin congestion. The authors contendthat these rates are of more practi-cal interest than traditional rates.This approach can be used to finetune the parameters of an incidentdetection algorithm and to comparedifferent types of incident detectionalgorithms.UCB-ITS-PWP-2000-11*August 2000, 5 pages, $5

Structure of the Transition ZoneBehind Freeway QueuesJuan Carlos Muñoz, CarlosDaganzoObservations of freeway trafficflow are usually quite scatteredabout an underlying curve whenplotted versus density or occu-pancy. Although increasing thesampling intervals can reduce the

lationships, technology, and trav-eler response to TravInfo, with rec-ommendations and conclusions.UCB-ITS-PRR-2000-7*May 2000, 81 pages, $15

Operations at Regional TravelerInformation Centers: The Case ofthe TravInfo Field OperationalTest – Final ResultsMark A. Miller, Dimitri LoukakosThe evaluation of the Traveler In-formation Center (TIC) consistedof technical and institutional ele-ments. The technical componentexamined system reliability, thecommunications interface, opera-tor work setting, and operator per-formance. The institutional analy-sis element examined the TIC’s op-erational effectiveness from an or-ganizational perspective, includingthe identification of both areas ofachievement as well as barriers tosuccessful TIC operations.UCB-ITS-PWP-2000-20*September 2000, 2 pages, $15

TravInfo Evaluation (TechnologyElement) Traveler InformationCenter (TIC) Study: OperatorResponse Time AnalysisMark A. Miller, Dimitri LoukakosResponse time, defined as the timeelapsed from information’s beingcollected from the HighwayPatrol’s computer-aided dispatchsystem until its dissemination tothe public, averaged eleven min-utes, though there were significantresponse time differences amongthe operators. Once TravInfo op-erations have become more auto-mated, operator response timesshould be reduced and overall op-erator productivity increased.UCB-ITS-PWP-2000-9*August 2000, 4 pages, $10

TravInfo Field Operational TestEvaluation: Information ServiceProviders Customer SurveyY.B.Youngbin YimThe survey addressed the usage ofWeb site information and thetravel behavior of Web site users.The key finding is that Web site ser-vice may significantly influencetravel behavior. The study showedthat drivers who encounter trafficcongestion on a frequent basis arelikely to access information on aregular basis.UCB-ITS-PWP-2000-5*May 2000, 3 pages, $5

TravInfo Field Operational TestEvaluation: Target Study FinalResultsRonald Koo, Y.B.Youngbin YimFocus of the study was threefold:1) understanding the extent to

which incident information influ-ences travel decision; 2) measur-ing the effects of incident informa-tion on overall travel patterns; and,3) assessing the benefits of inci-dent reports to travelers. It wasfound that although commuterstended to believe that their normaltravel plans were faster or as fastas alternate plans, traffic informa-tion was valued for intangible ben-efits, such as reducing driver anxi-ety or stress.UCB-ITS-PWP-2000-3*March 2000, 6 pages, $5

TravInfo Field Operational TestInstitutional Evaluation FinalResultsY.B.Youngbin Yim, Elizabeth DeakinFinal analysis of a three part seriesdealing with institutional evalua-tions of the TravInfo Field Opera-tional Test. The evaluations exam-ined TravInfo’s open architectureand its collaborative public privatepartnership in dis-seminating trav-eler information and fostering pri-vately offered advanced travelerinformation services in a commer-cial market.UCB-ITS-PWP-2000-2*February 2000, 8 pages, $15

User Response to the TelephoneAdvisory Traveler InformationSystem in the San Francisco BayArea: Based on TravInfo CallerSurvey Wave 1Jean-Luc Ygnace, Ronald Koo,Y.B.Youngbin YimKey findings of the survey revealthat those who called for eithertraffic or transit information weresatisfied with the service. Approxi-mately one third of those whocalled TravInfo modified theirtravel behavior after making theircall.UCB-ITS-PWP-2000-8*July 2000, 8 pages, $10

Vehicle to Roadside Communica-tions Architecture for ITS Applica-tionsTetiana Lo, Pravin VaraiyaPresents a framework for assistingIntelligent Transportation Systems(ITS) providers in deploying ITSuser services that require wide-areawireless communications. TheSHIFT programming language wasused to investigate the uplink per-formance of Cellular Digital PacketData, a leading wireless candidate.Focus was on examining its abilityto support vehicle-to-roadside ITSapplications during normal peak-period conditions and during amajor incident.UCB-ITS-PRR-2000-3*March 2000, 05 pages, $30

PATH Publications

29

APTS (Advanced PublicTransportation Systems)

Carlink–A Smart Carsharing Sys-tem Field Test ReportSusan Shaheen, John Wright,David Dick, Linda NovickResults from the field test ofCarLink, a smart carsharing systemthat combines short-term rentalvehicles with commun-ication andreservation techno-logies to facili-tate shared-vehicle access. Resultsinclude: operational understand-ing, participant profiles, behavioralfindings, economic viability, anddirections for future research.UCB-ITS-PRR-2000-10*May 2000, 200 pages, $25

Field Survey of Site Visits to Pas-senger Intermodal TransferFacilities in CaliforniaChris Mitchell, Mark A. MillerThirteen site visits were conductedat passenger intermodal transferfacilities in the San Francisco BayArea, San Diego, and the Sacra-mento area. Each visit consideredfour stages of the intermodal trans-fer experience: approach to the fa-cility, ticketing, transfer within thefacility and departure from it.Comparisons and contrasts aremade across regions and modesleading to the formation of gener-alized hypotheses regarding inter-modalism that will be tested laterin the project.Tech Note 2000-1*July 2000, 2 pages, $10

Institutional Aspects of Bus RapidTransit–A Macroscopic Examina-tionMark A. Miller, Stephen M. BuckleyInvestigates the institutional aspectsof Bus Rapid Transit through a mac-roscopic examination of relevantissues ascertained through a litera-ture review, a series of project teambrainstorming meetings, and inputfrom members of the Federal Tran-sit Administration’s Bus Rapid Tran-sit staff. Several dozen issues weregrouped into nine categories: in-tergovernmental and inter-organi-zational; intra-transit agency; po-litical; public relations and market-ing; funding and finance; labor;safety and liability; planning andland use; and the physical environ-ment.UCB-ITS-PWP-2000-7*July 2000, 25 pages, $10

Personalized Demand ResponsiveTransit Systems (PDRT)Y.B. Youngbin Yim, Asad J. Khattak

We examine factors likely to influ-ence people’s decision to take “on-demand” PDRT (like an airportshuttle service, where a van makesmultiple stops) and “fixed-sched-ule” PDRT (pick-ups and drop-offsmade at fixed, convenient loca-tions). The results of six focusgroups and the survey indicatethat a reliable, reasonably pricedPDRT service can be successful.Respondents were quite realistic intheir expectations about the PDRTservice attributes, especially thelonger travel times and wait timesinvolved in using PDRT.UCB-ITS-PWP-2000-22*October 2000, 2 pages, $5

Decision Support and Benefit/Cost Analysis

Cost-Benefit Analysis of Home-Based TelecommutingKevan R. ShafizadehEvaluates costs and benefits ofhome-based telecommuting.Combining empirical data fromthe literature with a Monte Carlosimulation technique, a distribu-tion of cost-benefit ratios is pro-duced from three perspectives: theemployer, the telecommuter, andthe public sector. This report iden-tifies situations during whichtelecommuting is most attractiveas a travel demand measure to itsprimary stakeholders: the tele-commuter and the employer.UCB-ITS-PRR-2000-20*November 2000, 137 pages, $20

Costs and Benefits of Telecom-muting: A Review and Evaluationof Micro-Scale Studies and Pro-motional LiteratureKevan R. Shafizadeh, Patricia L.Mokhtarian, Debbie A. Niemeier,Ilan SalomonFour small-scale telecommutingpilot project studies that take intoaccount costs and benefits are re-viewed for their methodology andassumptions. The report identifiescommon inputs, critical assump-tions, and limitations of the stud-ies. Major findings of each studyare presented and compared toclaims found in promotional litera-ture. It is found that few pilotevaluations contained cost-benefitresults.UCB-ITS-PRR-2000-13*August 2000, 58 pages, $15

Deploying Electronic TollsDavid Levinson, Elva ChangExamines the deployment of elec-tronic toll collection (ETC) and de-velops a model designed to maxi-mize social welfare associated with

the toll plaza. A payment choicemodel is developed to estimate theshare of traffic using ETC as a func-tion of delay, price, and a fixedcost of acquiring the in-vehicletransponder. The model is appliedto the Carquiñez Bridge in Califor-nia. The authors conclude thestudy with the recommendationthat the pace of deployment onthe bridge take into account thenumber of dedicated ETC lanesand the appropriate ETC discount.UCB-ITS-PRR-2000-11*May 2000, 29 pages, $10

Measuring the Aggregate Produc-tivity Benefits from ITS Applica-tions: The California ExperienceDavid Gillen, Matt HaynesFocuses on the productivityeffects of Intelligent TransportationSystems (ITS). Two types of mod-els are used to measure productiv-ity. The first involves a productionfunction estimate using countylevel data for California. The sec-ond method is to calculate totalfactor productivity measures anddetermine the impact of the intro-duction of ITS applications on acounty’s productivity.UCB-ITS-PWP-2000-17*September 2000, 05 pages,$20

PATH ATMIS: State of the Re-search Annual Report Fiscal Year1999/2000Robert TamIn each of the brief project descrip-tions we state the objectives of theproject and outline its status andsome of its principal results. Takentogether, the collection of projectdescriptions should give the readeran overview of the entire ATMISresearch program. In general wehave described only projects thathave been completed or have pro-duced specific results and report;thus a number of projects inprogress are not cited.UCB-ITS-PWP-2000-19*October 2000, 4 pages, $10

Productivity Benefits and CostEfficiencies from ITS Applicationsto Public Transit: The Evaluationof Automatic Vehicle Location(AVL)David Gillen, Elva Chang, DougJohnsonExamines the impact of AVL appli-cations on productivity and re-source in transit agencies by usingTotal Factor Productivity (TFP)techniques. Data used from theFederal Transit Commission’s data-base is augmented with informa-tion on AVL applications. Con-cludes that AVL has a positive im-pact on transit firm productivity

when output is measured as rev-enue vehicle miles or passengermiles.UCB-ITS-PWP-2000-16*September 2000, 8 pages, $15

Whence Induced Demand: HowAccess Affects ActivityDavid Levinson, Seshasai KanchiAs a result of additional highwaycapacity, workers spend less timetraveling. Non-workers, by con-trast, travel more. This points outthe differences in discretionary andnon-discretionary activities forworkers and non-workers. It alsosuggests that there are real gainsfrom capacity in people’s lives, atleast in the short term, as it is time,and not vehicle miles traveled, thatindividuals base decisions on.UCB-ITS-PWP-2000-21*October 2000, 1 pages,$5

30

PATH Publications

Advanced Vehicle Location

Aggregation of Direct and Indi-rect Positioning Sensors for Ve-hicle GuidanceAlice Agogino, Susan Chao,Jiangxin Wang, Xinyan DengAdvanced Vehicle Control Systems(AVCS) require large numbers ofsensors for different levels withinthe control hierarchy. Whereas allsensors contain uncertainty tosome degree, different sensors areparticularly useful for specific en-vironmental conditions. There-fore, sensor redundancy is essen-tial to achieving high sensor datafidelity for use in real-world, non-ideal, unpredictable environ-ments. In this work, a positioningsensor system, which includesGlobal Positioning System (GPS)receivers, a radar sensor, and a lin-ear transducer is investigated.UCB-ITS-PRR-2000-24*December 2000, 47 pages, $10

Feasibility of a Gyroscope-freeInertial Navigation System forTracking Rigid Body MotionChin-Woo Tan, Kirill Mostov, PravinVaraiyaExamines the feasibility of design-ing an accelerometer-based gyro-scope-free inertial navigation sys-tem that uses only accelerometersto compute the linear and angu-lar motions of a rigid body. Amodel for a micro-machined ac-celerometer is developed and theaccelerometer output equation isderived to relate the linear andangular motions of a rigid body

dvancedehicleontrol andafetyystems

AVCSS

with respect to a fixed inertialframe. An algorithm is developedto compute both the angular andlinear motions.UCB-ITS-PRR-2000-9*May 2000, 5 pages, $10

Integration of GPS-aided INS intoAVCSSJay Farrell, Matthew BarthResults of an effort to implementand analyze the performance a ve-hicle control system using controlstate information obtained from acarrier phase Differential GlobalPositioning System (DGPS) aidedInertial Navigation System (INS).Advantages include: no changes tothe highway infrastructure are re-quired; knowledge of a vehicle’sDGPS position allows the use ofmore path preview informationthan alternative systems; the navi-gation system would output posi-tion, velocity, and attitude, plusinertial measurements, at signifi-cantly higher rates than alternativenavigation systems.UCB-ITS-PRR-2000-22*December 2000, 8 pages, $15

Aerodynamics

Field Experiments DemonstrateFuel Savings for Close-FollowingMark Michaelian, Fred BrowandDescribes field experiments whichshow that fuel savings for indi-vidual vehicles in a platoon variedfrom 0-10 percent, dependingupon the number of vehicles, ve-hicle spacing, and vehicle positionwithin the platoon. Fuel savingsincreased with additional vehiclesand with shortened vehicle spac-ings. Interior vehicles were shownto gain the greatest benefits. Theaverage vehicle drag and averagefuel consumption are decreased byclose-following.UCB-ITS-PRR-2000-14*August 2000, 5 pages, $10

Transient Platoon AerodynamicsDuring Passing Maneuvers andIn-line OscillationsL. Tsuei, Ö. Savas, J.K. HedrickInvestigates transient effects as avehicle model is moved longitudi-nally parallel to a four-car platoon.Drag and side forces experiencedby each platoon member are mea-sured using strain gauge balances.Effects of the lateral spacing andrelative velocity between the pla-toon and the passing vehicle areinvestigated.UCB-ITS-PRR-2000-26*December 2000, 7 pages, $15

AHS Tools Development

Roadway and Work CrewConspicuityJoseph E. Barton, James A. MisenerQuantitatively addresses the mea-surement of conspicuity of high-way features and Caltrans workzones—from the perspective ofdriver detection. The method fo-cused on acquiring and operatingon a computational visual signa-ture analysis tool, but it evolvedinto evaluating the detection pro-cess, then selecting and exercisinghuman perception-acquisitionmodels suitable for developmentinto a tool for conspicuity mea-surement. A composite, quantita-tive model of conspicuity was de-veloped, verified, and applied tosome sample roadside scenes.UCB-ITS-PRR-2000-23*December 2000, 89 pages,$15

SmartAHS and SHIFT Enhance-ments, Persistence and QueryInterpretationJames MisenerDescribes the fine-tuning of thedevelopment of SmartAHS, a soft-ware system for microsimulation ofautomated highway systems (AHS)design and scenarios. SmartAHS isused for design, analysis and evalu-ation of AHS. SHIFT, theSmartAHS/Hybrid Systems ToolsInterface Format, is the simulatorfor user-defined AHS architectures.SHIFT also provides specificationsfor a high-level language used tospecify AHS-specific models forhighway layout, vehicle dynamics,actuators and sensors.UCB-ITS-PRR-2000-6*March 2000, 8 pages,$15

AHS Concepts

Safety and Throughput Analysisof Automated Highway SystemsDatta N. Godbole, John LygerosInvestigates the effect of differentdesign alternatives on the safetyand throughput that can be ex-pected if automated highway con-cepts are implemented. The au-thors identify intervehicle coordi-nation, on-line braking capabilityestimation, and platoon organiza-tion as the most important param-eters in braking capability.UCB-ITS-PRR-2000-1*January 2000, 9 pages, $10

AHS Deployment

Systematic Design for RoadwayInterfaces with Application toAutomated HighwaysRandolph HallThe central concept explored inthis report is how to design a road-way system that comprises mul-tiple layers, some of which are de-signed for accessibility, and othersof which are designed more for thepurpose of speed and capacity.The interface between an auto-mated highway system and con-ventional roadways presents newchallenges for interface designed,which are explored in this paper.UCB-ITS-PWP-2000-26*December 2000, 7 pages, $15

Communication Systems

Vehicle to Roadside Communica-tions Architecture for ITS Applica-tionsTetiana Lo, Pravin VaraiyaPresents a framework for assistingIntelligent Transportation Systems(ITS) providers in deploying ITS userservices that require wide-area wire-less communications. The SHIFTprogramming language was used toinvestigate the uplink performanceof Cellular Digital Packet Data,aleading wireless candidate. Focuswas on examining its ability to sup-port vehicle-to-roadside ITS appli-cations during normal peak-periodconditions and during a major inci-dent.UCB-ITS-PRR-2000-3*March 2000, 05 pages, $30

Control of Heavy Duty Vehicles

Lateral Control of Heavy DutyVehicles for Automated HighwaySystem: Experimental Study on aTractor Semi-trailerPushkar Hingwe, Jeng-Yu Wang,Meihua Tai, Masayoshi TomizukaDescribes the experimental valida-tion of a linear model for tractor-semitrailer combinations and theimplementation of a linear robustcontroller. The goal of the projectis to demonstrate lane following byautomatic steering for tractorsemitrailer vehicles. The report de-scribes the hardware develop-ment, the actuators and the openloop response of the steering ac-tuator, and the results of the openloop tests.UCB-ITS-PWP-2000-1*January 2000, 7 pages, $10

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Human Driver Models

Model of Human Vehicle Driving –A Predictive Nonlinear Optimiza-tion ApproachGünther ProkopDriving is seen here as a modelpredictive control task where thedriver accumulates knowledgeabout the vehicle’s handling prop-erties. Human behavioral optimi-zation is reflected by using theprediction model to optimize con-trol inputs. Prediction models andcriteria are shown to depend onthe current driving situation andpersonal driver preferences. Re-sults from experiments performedin real world and in a driving simu-lator are reported.UCB-ITS-PRR-2000-19*October 2000, 67 pages, $25

Vehicle Braking Control

Advanced Braking Methods forLongitudinal Control of Commer-cial Heavy VehiclesLasse Moklegaard, Anna G.StefanopoulouDescribes research on the longitu-dinal control of commercial heavyvehicles (CHVs) equipped withnovel retarding actuators. The au-thors present nonlinear dynamicmodels and longitudinal controlalgorithms that coordinate vari-able compression brake mech-anics with service brakes for CHVs.UCB-ITS-PRR-2000-8*May 2000, 50 pages, $10

Vehicle Control

Dynamic Modeling and Simula-tion of Snowplow: NormalOperation and Icepack ImpactsKun Zhou, Masayoshi Tomizuka,Wei-Bin ZhangA general method of deriving dy-namic models for any multi-bladesnowplow is presented. A snowmodel is presented to estimate thecasting forces, which act on theblades. Finally, an icepack-impactmodel is presented to simulate thedynamic performance of thesnowplow under impact caused bythe icepack. It is shown that bychanging the rear tire stiffness af-ter impact, the yaw motion and thelateral motion of the snowplow canbe remarkably reduced.UCB-ITS-PRR-2000-21*December 2000, 28 pages, $10

Vehicle Control Experiments andField Tests

Experimental Studies on HighSpeed Vehicle Steering Controlwith Magnetic Marker Referenc-ing SystemHan-Shue Tan, Bénédicte BouglerDescribes research focusing onconducting robust automatic ve-hicle steering control at highwayspeed based on a look-down lat-eral sensing system. Examines thevalidity of the installation of addi-tional magnetometers to create avirtual sensor in front of the vehicleto improve the look-ahead capa-bility. Details the general develop-ment of the automated steeringvehicle based on roadway mag-nets, and analyzes results of theinfluence of the suspension roll dy-namics to vehicle steering control.UCB-ITS-PWP-2000-6*May 2000, 76 pages, $15

Modeling, Design and Implemen-tation of Longitudinal ControlAlgorithm for Automated VehicleMergingXiao-Yun Lu, Han-Shue Tan, StevenE. Shladover, J. Karl HedrickFocuses on the implementation ofa newly developed algorithm forgeneral merging of vehicles into ahighway. A general longitudinalcontrol problem for vehicle merg-ing is first proposed. A general real-time adaptive closed-loopalgorithm that generates a smoothreference trajectory for the merg-ing vehicle according to the speedof the main line vehicle is then pre-sented. The concept of virtual pla-tooning is proposed to make thealgorithm adapt to different roadlayouts and to increase safety.UCB-ITS-PRR-2000-16*September 2000, 1 pages, $10

Nonlinear Longitudinal ControllerDevelopment and Real-timeImplementationXiao-Yun Lu, Han-Shue Tan, DanEmpey, Steven E. Shladover, J. KarlHedrickA dynamic sliding mode controllerand a dynamic back-stepping mul-tiple surface controller are imple-mented and compared to apreviously implemented adaptivesliding mode controller. The dy-namic back-stepping controllerfeatures a new type of integral fil-ter that was used to filter measuredsignals and estimating the deriva-tive of these signals in real-time.The controllers were implementedin real-time code and tested at lowand high speeds.

UCB-ITS-PRR-2000-15*September 2000, 5 pages $10

Vehicle Control Under AbnormalConditions

Vehicle Lateral Control UnderFault in Front and/or Rear SensorsJihua Huang, Guang Lu, MasayoshiTomizukaStudy of the behavior of existingvehicle lateral control systems inthe event of magnetometer fail-ures, with an eye to designing con-trollers that use the output fromonly one set of magnetometers,and developing an autonomouslateral control scheme that uses nomagnetometers.UCB-ITS-PRR-2000-25*December 2000, 8 pages, $10

Vehicle Safety Assessment andSafety Enhancement

Conditions for Safe Decelerationof Strings of VehiclesJohn Lygeros, Nancy LynchPresents a model that can accountfor the possibility of repeated col-lisions between vehicles in a string,and that specifies safe conditionswhen the string performs a simpleemergency deceleration maneu-ver. Discusses implications of theresults for safe vehicle platooning.UCB-ITS-PRR-2000-2*January 2000, 41 pages, $10

Safety Evaluation of Vehicle Fol-lowing Operations by Fault Treeand Sensitivity AnalysisChing-Yao ChanUsing the software tool CAFTA forWindows, the author evaluatedfault-tree analysis of two differentscenarios: 1) vehicle-following col-lision fault tree analysis; and, 2)lane-keeping fault tree analysis.UCB-ITS-PRR-2000-18*September 2000, 7 pages, $10

Studies of Collisions and ControlStrategies in Vehicle FollowingOperations by Two-DimensionalImpact SimulationChing-Yao ChanDescribes the investigation bysimulation of the problem of ap-plying steering control in vehicle-following collisions. The feasibilityof maintaining vehicle trajectoriesfollowing a collision was investi-gated with a vehicle collisionmodel and a feedback controller.The collision controller design isformulated as an impulse distur-bance rejection. A look-aheadsteering controller is then pro-

posed, based on the performancerequirements of the steering con-trol in collisions.UCB-ITS-PRR-2000-17*September 2000, 8 pages, $10

Roadway and Work CrewConspicuity

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PATH Publications

PATH Publications

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PATH Database

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PATH DatabaseThe California PATH Database provides access to the largest and mostcomprehensive collection of bibliographic information on Intelligent Trans-portation Systems (ITS). The Database is now accessible on the Internetthrough a partnership between the California PATH Program and theTransportation Research Board.

The Database, created in 1989, is sponsored by Caltrans and the FederalHighway Administration. It is maintained by the Harmer E. Davis Transpor-tation Library (HEDTL) at the Institute of Transportation Studies, Univer-sity of California at Berkeley. The web site is administered by the Transpor-tation Research Board and is updated monthly.

SCOPE AND COVERAGEThe Database contains references to all aspects of Intelligent Transporta-tion Systems, ranging from historical materials dating back to the 1940s totopics of current and international research and applications. It reflects awide coverage of information on ITS, including monographs, journal articles,conference papers, technical reports, theses, web sites, and selectedmedia coverage. Currently, there are over 25,000 records with abstracts containedin the Database. Full bibliographic information is provided, and URLs are includedfor documents that are available in electronic format. The majority of the indexeditems are held at the Harmer E. Davis Library.

ACCESS AND AVAILABILITYTo access the California PATH Bibliographic Database, go to:http://www4.nationalacademies.org/trb/tris.nsf/web/path

To access the Harmer E. Davis Library web site, go to:http://lib.berkeley.edu/ITSL/

The “New Acquisitions in Intelligent Transportation at the Harmer E. DavisTransportation Library” list is a compilation of records that have beenadded to the Database in the previous month. To access the New Acquisi-tions list, go to:http://lib.berkeley.edu/ITSL/newbooks.html

For information regarding the availability of documents held at otherUniversity of California at Berkeley libraries, go to:http://www.lib.berkeley.edu/ILS/nonuc.html

Loans and photocopies of materials are available to persons affiliated withthe University of California and California PATH sponsors. For others,information on interlibrary loans or photocopies may be obtained at theHEDTL web site. Questions regarding the Database may be directed to:Seyem Petrites, PATH Database Manager at:spetrite@library.berkeley.eduMichael Kleiber, PATH Database Librarian at:mkleiber@library.berkeley.edu

The PATH MagneticMarker GuidanceSystem has now beeninstalled for testing ordemonstration inCalifornia, Arizona,Alaska, Texas, TheNetherlands andJapan.

PATH Database

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