A GIS-T APPROACH TO HORIZONTAL CURVE DATA COLLECTION AND ASSESSMENT

2019 AASHTO GIS-T SymposiumBy James Brennan

CIO, Quality Countsjbrennan@qualitycounts.net

PRESENTATION OBJECTIVES

1. Safety motivation for horizontal curve warning signs

1. System for horizontal curve data collection

1. Practical application of GIS-T to data collection operations

MOTIVATION

MOTIVATION: SAFE DRIVING AT CURVES1. 37,133 traffic fatalities in United States in 2017

(NHTSA).

1. More than 25 percent of all highway fatalities at curves though curves are small portion of highway mileage.1

1. 85 percent of fatal crashes on horizontal curves are run-off-the-road crashes caused by vehicles moving at excessive speeds.2

1. Chevron Alignment signs can reduce crashes on horizontal curves by up to 25 percent, based on FHWA Roadway Departure Crash Reduction Factors.3

1. https://safety.fhwa.dot.gov/roadway_dept/countermeasures/horicurves/2. 23 CFR Part 655 (2009).3. Srinivasan et. al. (2009).

About QC2009 MUTCD MANDATE

About QC2009 MUTCD MANDATE: GOALSFrom 2010 Federal Register section explaining mandate:“(2019) Compliance date … established because of demonstrated safety issues associated with run-off-the road crashes at horizontal curves.”

• Consolidate sections relating to horizontal alignment

• Consistent usage of a few sign types

• Uniform design to provide consistency for road users

• Avoid Confusion with mixed application of several signing options

SIGNSFrom 2009 MUTCD

• Consistent usage of a few signs providing better driver communications rather than increasing confusion with mixed application of several signing options.

• Uniform design to provide consistency for road users.

Also

• Limited set of signs facilitates (partial) automation of assessments.

About QC2009 MUTCD MANDATE: SUMMARY

2C.02 Application of Warning SignsStrengthen language to state that all improper signs shall be removed by year end 2019.

2C.05 Advanced Placement Sign GuidanceThe Horizontal Alignment sign and Advisory Speed plaque placed on same pole in advance of the PC based Table 2C-4.

2C.06 Sign Usage StandardRequirements for utilizing horizontal curve advisory signing based on the differential in Speed Limit and Advisory Speed as in Table 2C-5.

2C.08 Advisory Speed Plaque StandardEstablished engineering practices for recommended advisory speedsA. AccelerometerB. Design speed equationC. Ball-bank indicator with 16, 14, and 12 degree model

2C.09 Chevron Spacing GuidanceChanged from having “two in view” at all times to requirements based on Advisory Speed and Curve Radius as in Table 2C-6.

Data Element

About QC

Example: Data Elements for Compliance with Table 2C-5For each curve, each direction, must know: location, geometry, speed limit, advisory speed, and existing horizontal alignment signs.

WHAT IS A DRONE

• AKA: UAS, UAV• A recording device that can fly

POSSIBLE ISSUES WITH EXISTING CURVE DATA1. No study documentation; unknown method of determining

advisory speed (e.g. ball-banking limits unknown).

1. Inadequate datafication of study documentation, e.g. as-builts, limits efficient analysis.

1. Changes in conditions (roadway geometrics, surface characteristics, or sight distance) imply each location should be evaluated periodically or when conditions change.

1. Lack of uniformity in studies challenges defensibility of methodology; required to follow established practices.

1. Preponderance of inaccurate (low) advisory speeds causes driver disrespect for advisory speeds at all curves.

1. No existing data on sign inventory and roadway geometry makes it impossible to demonstrate that signs conform to best practices.

PROJECT EXAMPLES

ACTIVITY DISTRIBUTION EXAMPLE

Transportation Agency (City, County, DOT, MPO, etc.)

Needs a horizontal curve assessment project completed.

Possesses existing GIS-T, Asset, and other framework data.

May have existing road geometry, sign, and superelevation data

which needs assessment.

Plan for utilizing project outputs in sign maintenance program.

Engineering Consultant, Data Collector (Integrator)

Users/integrators of devices for field data collection.

Users/integrators of software for project management, quality

control, data analysis.

Producers of engineering studies documenting horizontal curve

assessments.

Device/System Manufacturer(hardware, software)

Equipment for data collection: road geometry, sign inventory,

other assets, etc.

Software to assist with horizontal curve assessment report

generation.

Database for file and data management; database

administration.

ODOT HORIZONTAL CURVESSummary (Jul 2016- Mar 2017; 8 months)QC partnered with JMT to perform horizontal curve data collection and assessment on over 17,000 CLM + 5300 ramps maintained by ODOT.

GIS-T Map using ODOT TIMS Data• City, county, district boundaries• Interstate, US and state highways• Ramp locations• Segments with temporary/long term

construction• Segments designated for resurveying• Priority order of data collection by county

within districts

ODOT HORIZONTAL CURVESTeam CoordinationPeak data collection• 10 vehicles• 20 data processing staff

Project Outputs• 15,000 curve assessment reports produced• 34,000 horizontal alignment warning signs• Summary Horizontal Curve Assessment

Report (HCAR) for all curves

About QCWSDOT SWR

About QCWSDOT SWR WITH CARS

Project Summary (May-June 2017)QC partnered with KAI for curve data collection and assessment on all 960 CLM miles of roadway and ramps maintained by Wash DOT’s SW Region.

WSDOT Geodata Distribution Catalog• Construct project GDB in QGIS• Project planning/tracking• Map visualizations for added QC• LRS data for curve locations

(PC/PT)

Project Outputs• 2,000 curve reports produced• CARS “Create Signs” function used

for baseline proposed sign data

CURVE ASSESSMENT

MODEL

INDEPENDENT HORIZONTAL CURVE• Point of curvature (PC) and point of tangency (PT)• Curve radius, curve length, deflection angle• Superelevation • Parabolic, circular, spiral curve

Side friction (as a function of vehicle speed) through curve

Vehicle speed at which a given level of side friction is achieved

Recommended Advisory Speed (RAS)

ROAD GEOMETRYOther Geometric Factors• Curve direction• Multi-curve assembly• Types: compound,

reverse• Horizontal curve series

Vertical Curve Geometry• Grade length• Percent gradient• Curve Grade

Segment Context

About QCSITUATIONAL DATA ELEMENTSA system for horizontal curve assessment may not contain certain data elements that are relevant for some curve assessments.

Situational Data• Vertical curve geometry• Ramp length• Other existing road signs• Intersection in curve• Existing roadside conditions such as striping,

lane width, clear zones, side slopes• Work zone conditions/temporary traffic

control• Sight distance, obstructions• Weather• Traffic operations, congestion

HORIZONTAL CURVE DATA COLLECTION SYSTEM

About QCIN VEHICLEIntegrated Data Collection Technologies

• Rieker CARS GPS-BBI system

• Dashboard camera (GoPro 7)

• Garmin navigation system

• Windows tablet and SD cards

• AGOL reference map

• Google forms driver log

About QCPROJECT GDB OVERVIEW

Framework (Agency) GIS Data• Road network• Mile markers• Posted/statutory speed limits• Ramp locations• Existing curve data• Sign inventory

QC Project GDB• Cloud file storage• Python agents and lists• ArcGIS Pro • AGOL Project Maps

Basecamp (Route Planning)• Map tracks, waypoints• Survey/Resurvey driving

routes• Generate driving route GPX

files

CARS (Curve Data)• Import mile markers• Raw GPS/BBI data uploads• Web portal data management• Curve analysis and reporting

SignProx (Sign Inventory)• Import road network/LRS data• Agency sign type database• Video log integration• Record sign inventory

Agency Data• Curve advisory

reports• Proposed signs• Existing signs

ROUTE PLANNING

About QCROUTING REFERENCE MAP

Track routing progress

Coordinate routing team

Schedule drivers

Verify comprehensive network coverage

Satisfy agency priority orders

Track construction locations

Plan resurveying efforts

About QCROUTE PLANNING• Manual selection of waypoints

• Estimated drive times used to schedule driving shifts with safe limits on hours driven before rest

• GPX routes are archived in cloud and distributed via web to field technicians

• Driver logs records: device or tablet anomalies, construction or other road obstructions, and miscellaneous project notes

About QCQC PORTAL: TRIPS

GPS-BBI: CURVE ASSESSMENT

About QCCURVE ADVISORY REPORTING SERVICE (CARS)Introduction• Developed by Rieker Inc.• Designed to meet MUTCD 2009

requirements for RAS calculations• Integrated dashboard mounted

inclinometer and GPS record data continuously

• Raw data timestamped GPS/BBI data recorded in real time

• Tablet application for admin

Device Set Up and Data Collection• Inclinometer calibration test (2 mins)• Install the dashboard mounted BBI• Verifying device is level relative to vehicle

axle (5 min)• Garmin navigation device

About QCCARS COVERAGE

About QCCARS CLOUD PORTAL

About QCMODELED CURVEMile MarkersGPS/BBI DatapointsModeled CurvePC/PT locations

Model Geometry• Curve radius• Curve length• Deflection

angle• Curve grade

SR 5 Q5 3744 MP 0.00

SR 5 Q5 3744 MP 0.11

CARS CURVE REPORT

PROPOSED SIGNSVisualization in CARS web portal

CARS “Proposed Signs” Function• Modeled curves• Existing agency GIS data• MUTCD rules

Saved as proposed signs to sign inventory database.

Assessments for independent horizontal curves

About QC

HORIZONTAL CURVE ADVISORY REPORT (HCAR)

Note: CARS summary report of advisory speeds and curve statistics for all curves, by direction, on all routes of the network.

About QCWSDOT SWR W/ CARS

C. Radosta, “SWR Curve Data Collection & Analysis Report," Technical Memorandum, Kittelson and Associates, 2017.

SIGN INVENTORY

SIGNPROX GIS INTEGRATION

SIGNPROX VIDEO INTEGRATION

GEOLOCATED SIGNS & ASSEMBLIES

About QCSIGN INVENTORY MAP

About QCSIGN ASSEMBLY REPORT

About QCSIGN DETAIL REPORT

QUALITY CONTROL

CURVE REVIEW MAP

Visual ReviewType II errorsPC/PT verification

DATA FLAG SYSTEMHorizontal Curve Reports• Geospatial Queries (Python and ArcPy)• Raw GPS data evaluated for comprehensive

segment coverage (including required BBI passes and video)

• Min/max test speed within each curve pass 5 mph

• PC/PT comparison with existing framework curve data

• Posted speed to available posted speed data• Side friction limit scheme verification based on

posted speed

Sign Inventory Data• Sample 10% of sign records and

segments for independent verification• Geospatial tests for sign codes based

on road network attributes• Sign groups within assemblies• Sign/assembly type combinations

Flag System Outputs• Segments, curves, and signs review list• Segments, curves, and signs reject list• Identify segments for resurvey list

About QCISSUE: CURVE DATA MANAGEMENTDatapoints• BBI readings every 0.05 seconds; GPS readings every 0.3

seconds => one day of driving produces 504,000 BBI datapoints.

• Best Practice: Automate curve assessment calculations.• Best Practice: GDB with data session, pass, curve, and sign

identifiers.

Data Session Size vs Number of Data Sessions• Tradeoff between file size and number of files• If a new data session is created every hour, a team of 10

drivers produces 350 data sessions per week.• Large data session increase computational requirements for

data processing.• Best Practice: Associate data sessions with road segments in

GIS-T geodatabase to facilitate tracking and evaluation.• Best Practice: One-hour CARS data sessions provide

satisfactory computational efficiency without making data session management difficult.

CONCLUSIONS1. Horizontal curve assessments are significant part of traffic safety.

1. GIS-T is essential for data collection operations on horizontal curve assessment projects.

1. Demonstrated practical use of GIS-T for:• Project tracking• Route planning• Sign inventory• Curve assessment• Quality control• Stakeholder verifiability

Contact InformationTHANK YOU!

James BrennanCIO, Quality Counts

Tigard, Oregonjbrennan@qualitycounts.net

www.qualitycounts.net