Southeast Michigan Council of Governments
Dec 13, 2015
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