Southeast Michigan Council of Governments

Brian D. Mohr, Li-yang Feng, and Tom BruffBrian D. Mohr, Li-yang Feng, and Tom BruffSoutheast Michigan Council of GovernmentsSoutheast Michigan Council of Governments

1111thth TRB Applications Conference TRB Applications ConferenceDaytona Beach, FLDaytona Beach, FLMay 7, 2007May 7, 2007

Development of a Traffic Development of a Traffic Count Database for Travel Count Database for Travel

Model CalibrationModel Calibration

**DetroitDetroit

SEMCOG RegionSEMCOG Region

St. Clair

MacombOakland

Livingston

Washtenaw Wayne

Monroe

Population:Population:4.9 million4.9 million

Licensed drivers:Licensed drivers:3.4 million3.4 million

Annual VMT:Annual VMT:49 billion49 billion

Miles of road:Miles of road:23,00023,000

Communities: Communities: 234234

Presentation OverviewPresentation Overview

Regionaltraffic count

database

Travel modelinterface

Countsource

Countsource

Countsource

Modelvalidation

files

• No consistency in count data formatNo consistency in count data format

• No central database for storing countsNo central database for storing counts

• No efficient procedure for linking No efficient procedure for linking counts with modelcounts with model

• No way to determine if counts sufficient No way to determine if counts sufficient for validationfor validation

ChallengesChallenges

• Create regional traffic count database Create regional traffic count database (RTCD)(RTCD)– Central repository for all countsCentral repository for all counts– Source of counts for model, other appsSource of counts for model, other apps

• Create automated procedure for linking Create automated procedure for linking counts with modelcounts with model

• Use power of GIS (linear referencing)Use power of GIS (linear referencing)

SolutionsSolutions

• Transferring data from multiple sources Transferring data from multiple sources into common formatinto common format– Michigan Department of Transportation Michigan Department of Transportation

(MDOT)(MDOT)

– Local agencies (counties, cities)Local agencies (counties, cities)

• Developing RTCD database structureDeveloping RTCD database structure

• Coding counts with GIS attributesCoding counts with GIS attributes

RTCD Development IssuesRTCD Development Issues

• Software featuresSoftware features– Web-based, friendly user interfaceWeb-based, friendly user interface

– Direct uploading from traffic countersDirect uploading from traffic counters

– Logical relational database structureLogical relational database structure

– Numerous quality control measuresNumerous quality control measures

• Provides SEMCOG easy access to Provides SEMCOG easy access to counts from all seven counties, Detroitcounts from all seven counties, Detroit

Traffic Count Database Traffic Count Database System (TCDS)System (TCDS)

• ChallengesChallenges– Understanding MDOT’s count programUnderstanding MDOT’s count program

– Three types of data: PTR, ITS, short countsThree types of data: PTR, ITS, short counts

– Different data format for each typeDifferent data format for each type

• Solution: MDOT data conversion toolSolution: MDOT data conversion tool– Converts all data into common formatConverts all data into common format

– Flags “representative” PTR, ITS countsFlags “representative” PTR, ITS counts

Importing MDOT’s Traffic Importing MDOT’s Traffic Count DataCount Data

MDOT Data Conversion ToolMDOT Data Conversion Tool

• Oracle database with three primary tables:Oracle database with three primary tables:– Count location descriptionsCount location descriptions

– CountsCounts

– GIS (linear referencing) codingGIS (linear referencing) coding

• Number of records in databaseNumber of records in database– Locations: Locations: 28,08028,080

– Counts available for validation: Counts available for validation: 58,75058,750

– Total counts available: Total counts available: 342,049342,049

SEMCOG’s Regional Traffic SEMCOG’s Regional Traffic Count Database (RTCD)Count Database (RTCD)

• Counts coded with LRS attributes from Counts coded with LRS attributes from base map (route/milepoint system)base map (route/milepoint system)

• All SEMCOG transportation data codedAll SEMCOG transportation data coded

• Counts coded as segmentsCounts coded as segments

GIS (Linear Referencing) GIS (Linear Referencing) CodingCoding

Every point ( ) on road network represented by two coordinates: route number, milepoint

Every count location ( ) represented by three coordinates: route number, beginning milepoint, ending milepoint

RegionalTraffic Count

Database(RTCD)

Local agencycounts

(via TCDS)

MDOT counts(via conversion

Tool)

Othercounts

RegionalTraffic Count

Database(RTCD)

Travel modelinterface

Local agencycounts

(via TCDS)

MDOT counts(via conversion

Tool)

Othercounts

Modelvalidation

files

• Required inputRequired input– RTCD tables (locations, counts, GIS info)RTCD tables (locations, counts, GIS info)

– TransCAD link definition tableTransCAD link definition table

– Count alignment tableCount alignment table

– Desired statistical parametersDesired statistical parameters

• Output: data-based or model-based Output: data-based or model-based validation filevalidation file

Model Validation File Model Validation File CreatorCreator

• Data-basedData-based– Links assigned counts wherever possibleLinks assigned counts wherever possible

– Not a statistically sound validation fileNot a statistically sound validation file

• Model-based (statistical sample)Model-based (statistical sample)– Links stratified by geographic area and Links stratified by geographic area and

functional class, sample randomly selectedfunctional class, sample randomly selected

– Only some links will have counts assignedOnly some links will have counts assigned

Two Types of Model Two Types of Model Validation FilesValidation Files

Model Validation File Model Validation File CreatorCreator

Model Validation File Model Validation File CreatorCreator

• Model links also coded with LRS Model links also coded with LRS attributes from GIS base mapattributes from GIS base map

• Allows geographic comparison of Allows geographic comparison of count locationscount locations and and model linksmodel links

Matching Counts and Links Matching Counts and Links Using Linear ReferencingUsing Linear Referencing

• Count attributes used to match counts Count attributes used to match counts with appropriate model linkswith appropriate model links

• Hierarchy of preferred counts developedHierarchy of preferred counts developed• Examples of preferred countsExamples of preferred counts

– Counts taken in same year as model Counts taken in same year as model validation yearvalidation year

– Directional countsDirectional counts– Counts with shorter intervalsCounts with shorter intervals

Multiple Counts at Same Multiple Counts at Same LocationLocation

• Entire process works successfullyEntire process works successfully– Already used on 2002, 2005 highway Already used on 2002, 2005 highway

networks in current modelnetworks in current model

– Will be used soon with 2006 countsWill be used soon with 2006 counts

• RTCD data used in many transportation RTCD data used in many transportation applications, including web data toolapplications, including web data tool

ResultsResults

www.semcog.org

• Continue to improve count data qualityContinue to improve count data quality

• Append data from additional sources Append data from additional sources into RTCDinto RTCD

• Fully automate importing of data into Fully automate importing of data into RTCDRTCD

• Begin performing model validation with Begin performing model validation with statistically generated sample of linksstatistically generated sample of links

Future InitiativesFuture Initiatives

• Establishing data formatting consistency Establishing data formatting consistency • Effective communication, coordination Effective communication, coordination

with local agencies and MDOTwith local agencies and MDOT• Establishing data quality controls Establishing data quality controls

throughout processthroughout process• Use of GIS (linear referencing)Use of GIS (linear referencing)• Automating tasks wherever possibleAutomating tasks wherever possible

Keys That Made This Keys That Made This Project SuccessfulProject Successful

RegionalTraffic Count

Database(RTCD)

ModelValidation

File Creator

Local agencycounts

(via TCDS)

MDOT counts(via conversion

tool)

Othercounts

Data-basedvalidation

files

Model-basedvalidation

files

SEMCOGwebsite

Othertransportationapplications

Brian D. Mohr, Li-yang Feng, and Tom BruffBrian D. Mohr, Li-yang Feng, and Tom BruffSoutheast Michigan Council of GovernmentsSoutheast Michigan Council of Governments

1111thth TRB Applications Conference TRB Applications ConferenceDaytona Beach, FLDaytona Beach, FLMay 7, 2007May 7, 2007

Development of a Traffic Development of a Traffic Count Database for Travel Count Database for Travel

Model CalibrationModel Calibration