Incident Management in Central Incident Management in Central Arkansas:Arkansas:

Current Settings and Proposed Current Settings and Proposed ExtensionsExtensions

Weihua XiaoYupo Chan

University of Arkansas at Little Rock

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Traffic Incident Traffic Incident ManagementManagement

• The cost of total delay in rural and urban areas is estimated by the USDOT to be around $1 trillion per year…Well over half of nonrecurring traffic delay in urban areas and almost 100% in rural areas are attributed to incidents… USDOT estimates that the crashes that result from other incidents make up 14-18% of all crashes (National Conf. On TIM, 2002).

• Effective incident management can decrease secondary crashes, improve roadway safety and decrease traffic delays.

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Benefits of Traffic Incident Benefits of Traffic Incident Management (TIM) ProgramsManagement (TIM) Programs

TIM Program Benefits

Brooklyn, NY The average time to clear all types of incidents was reduced 66 percent, from 1 ½ hours to 31 minutes.

Philadelphia’s Traffic and Incident Management Program

Decreased freeway incidents by 40 percent, and reduced freeway closure time by 55 percent.

Maryland’s Chesapeake Highway Advisories Routing Traffic program

Reported a benefit/cost ratio of 5.6:1 with a savings of 2 million vehicle-hours of delay per year from incident-related congestion.

San Antonio’s TransGuide Reduced crashes by 35 percent, and secondary crashes by 30 percent on its urban freeways.

Atlanta The maximum time from incident verification to lane clearance was cut from 6 1/4 hours to 1 1/2 hours, resulting in an estimated decrease of 2 million vehicle-hours of delay per year.

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Time Line of an Incident Duration

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Incident Management Incident Management ActivitiesActivities

• Motorist Assistance Patrol (MAP) – 3 vehicles operating on I-30, I-40, I-630, I-430, and I-440 in the urbanized

area.– Proposed to provide some coverage of both US 67/167 and I-530, from I-

30 to Dixon Road • Towing and Wrecker Service

– A rotation list of qualified towing and wrecker services.– Current procedures do not specify a minimum response time.

• Emergency Medical Services (EMS) – 911 calls– Communications upgrades are needed.

• Traffic Management at Work Zones (Meadors 2002) – Queue detectors – Variable message signs (VMS) and highway advisory radio (HAR)

• Traveler Information System– 511 calls

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Goals of our StudyGoals of our Study

Assess the negative impact of incidents using simulation technology.

Evaluate the overall performance of the incident management program.

Identify those factors that increase chances of incidents via data-mining technology.

Improve incident detection efficiency, accuracy, and response strategy in general

Enhance incident site management strategies to reduce the negative impact of incidents.

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Study AreaStudy Area

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Major Travel Corridors

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ImplementationsImplementationsIncident Data Analysis and Incident Data Analysis and

ModelingModeling• Incident Occurrence Model

– Poisson or Negative binominal?– What factors affect the occurrence of incidents: speed

limit, lanes, weather, intersections, etc.

• Incident Duration Model– Normal distribution? Lognormal distribution?– Parameters?

• Blocked-lane Model– The relationship between number of blocked lanes and

incident characteristics

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ImplementationsImplementationsSimulation Based Decision Support Simulation Based Decision Support

SystemSystem• Evaluate current incident management program.

• Predict the effects of changes or upgrades.

Incident Generation

Incident Response

Location

Occurrence time

Clearance time

Detection time

For Each Incident

Traffic Simulation

Update link travel times

Track status of service vehicles

Update incident waiting list

Update incident duration

Choose current response incident

according to dispatching policy

Identify proper service vehicle to

response the incident

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ImplementationsImplementations Enhancement of Incident Enhancement of Incident

DetectionDetection

INDUCTIVELOOP DETECTORS

OTHER DETECTORS• VIDEO DETECTORS• SONAR DETECTORS• RADAR DETECTORS

CELLPHONES

REMOTE SENSORS

654321

(Mirchandani, 2003)

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ImplementationsImplementationsEnhancement of Incident detectionEnhancement of Incident detection

• Choose the right location to install the sensors.

• Efficient incident detection algorithm.

• Locate the cell phone caller quickly and precisely.

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Analysis and Modeling of Traffic Incident Data

Incident Delay

Analysis

Simulation-Based Decision Support System

Enhancing Incident

Detection

Optimal Traffic Management at

Incident Site

O-D pair database

Traffic volume predication model

Identify optimal traffic reroute strategy

HAR/VMS

Identify the location of cell caller more precisely

Improve Incident detection algorithm

Choose the right place to install incident detection

devices

Incident generation module

Traffic simulation module

Incident response simulation module

Deterministic queuing model

Queuing theory model

Traffic simulation

ImplementationsImplementations

A

B

CTraffic

incident

D

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• GPS, Remote sensing & GIS Lab

• Telecommunications and Transportation Lab

• Virtual Reality Center

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Incident Data of Arkansas collected Incident Data of Arkansas collected fromfrom

Bureau of Transportation Statistics Bureau of Transportation Statistics (BTS)(BTS)

Fatal traffic crashesFatal traffic crashes• Interested information– City, County, Weather, Day of Week, Day of Month, Month,

Year, Fatalities, Injuries, Lanes, Light Condition, Mile point, Speeding, Speed, Speed limit, Surface Condition, Pavement Type

470

480

490

500

510

520

530

540

550

560

570

580

Nu

mb

er

of

fata

cra

sh

es

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001Year

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We need more detailed data…We need more detailed data…

• Locations of incidents: route, mile post, speed limit, number of lanes, number of blocked lanes, horizontal grade, vertical grade, traffic volume, etc.

• Incident response: response time, incident duration, etc.

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SummarySummary

• negative consequences are by no means negligible in small and medium communities

• an incident management plan that is articulated with an ITS architecture.

• analysis and modeling of historical incident data • the right intersections to install incident-detection devices • incident-generation module in the incident-management

simulation software • ITS metaLAB with close cooperation with other regional

stakeholders • a case study for other communities of similar population size and

structure

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Thank you!Thank you!

Questions and Comments