Conversion of Volunteer-Collected GPS Diary Data into Travel Time Performance MeasuresPC : Terry KeenerPD : Michael ChamberlainPI : Chandra R. Bhat Barbara ParmenterResearchersSiva SrinivasanPrabuddha GhoshAruna SivakumarAarti KapurStacey BrickaTraining Workshop on the Use of GPS-TDG Software

Presentation OverviewBackgroundResearch ObjectivesConceptual Structure of GPS-TDGSoftware OverviewTutorial using Sample Data from LaredoPreprocessing GPS streamsBasic AnalysisEnhanced AnalysisQuerying and Aggregation

Background: Collecting Travel Data

Background: Enhancing Travel Data CollectionSurvey Design EnhancementsTrip diariesActivity diariesTime-use diaries

Using GPS in Travel Surveys: Different TechnologiesIn-Vehicle devicesHand-held devicesPurely passiveRequiring additional active inputOur focus

Advantages of GPS-based Data CollectionPassive Data CollectionReduces respondent burdenAddress under-reporting of tripsAddress item non-responseIncreased Spatial and Temporal AccuracyDestination locations for non-frequent tripsTrip times and time-of-day of travel are not estimates Additional DataTrips missed in manual reportingRoute choiceTravel speeds

Issues with Passive-GPS Data CollectionData is collected in the form of navigational streamsRequires operational definitions of trips and stopsRequires substantial processing for converting into conventional trip-diary formatEquipment capabilities/accuracy/errors impacts trip identificationTrip purpose information unknownRequires supplemental user input (en-route or via prompted recall)Use of regional land-use and respondent demographics data for imputing trip purposesVehicle occupancy unknownRequires supplemental user input

GPS-based Travel Surveys: SummarySubstantial potential for using in-vehicle GPS technologies in travel surveys to enhance quality and quantity of data

Shifts considerable burden from the respondent to the analyst: Need to convert navigational streams from GPS devices to trip sequences

Research ObjectivesDevelop algorithm to identify vehicle trip characteristics from GPS navigational streamsImplement the algorithm in GIS-based software to automate travel-diary extractionAggregate the derived travel diaries to produce inter-zonal trip-tables by trip purpose and time of dayCompute inter-zonal highway performance measures (i.e., travel times and speeds)Develop a GIS-based software to automate the process of converting the raw GPS navigational streams into the conventional trip-diary format

Conceptual Overview of GPS-TDG

GPS-TDG: Primary User InterfaceData AreaDisplay of derived travel diaries and query resultsCommand AreaProviding inputs, querying, and overall controlMenu BarPreprocessing and help

View sample raw GPS streams Preprocess GPS streams & view the resultsRunning the software in the Basic Analysis modeProvide inputsView and interpret resultsRunning the software in the Enhanced Analysis modeProvide inputsView and interpret resultsAggregation and QueryingTutorial on Using GPS-TDG

Sample Raw GPS Stream (GeoLogger)RECTYPE,GPS_ID,HH_ID,Veh_ID,GMT_DATE,GMT_TIME,LOC_DATE,LOC_TIME,LAT_RAW,LONG_RAW,ELEV_RAW,VELOCITY,HEADING,HDOP,SATS5,272,1005402,1,03/25/02,12:40:37,03/25/02,06:40:37,27.59705,-99.47217,00179,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:38,03/25/02,06:40:38,27.59705,-99.47217,00179,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:39,03/25/02,06:40:39,27.59705,-99.47217,00180,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:40,03/25/02,06:40:40,27.59705,-99.47217,00180,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:41,03/25/02,06:40:41,27.59705,-99.47217,00180,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:42,03/25/02,06:40:42,27.59705,-99.47217,00180,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:43,03/25/02,06:40:43,27.59705,-99.47218,00179,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:44,03/25/02,06:40:44,27.59705,-99.47218,00179,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:45,03/25/02,06:40:45,27.59707,-99.47218,00179,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:46,03/25/02,06:40:46,27.59707,-99.47218,00178,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:47,03/25/02,06:40:47,27.59707,-99.47218,00178,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:48,03/25/02,06:40:48,27.59707,-99.47218,00177,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:49,03/25/02,06:40:49,27.59707,-99.47220,00177,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:50,03/25/02,06:40:50,27.59707,-99.47220,00177,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:51,03/25/02,06:40:51,27.59707,-99.47220,00176,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:52,03/25/02,06:40:52,27.59707,-99.47220,00176,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:53,03/25/02,06:40:53,27.59707,-99.47220,00176,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:54,03/25/02,06:40:54,27.59707,-99.47220,00176,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:55,03/25/02,06:40:55,27.59707,-99.47220,00176,0.00,000,01.7,055,272,1005402,1,03/25/02,12:40:56,03/25/02,06:40:56,27.59707,-99.47220,00175,0.00,000,01.7,05

Running the PreprocessorSelect the directory containing the raw streamsSelect the target directory for writing the processed streams

HREC,HDOP=5.0,Min Satellites=3GREC,272,1005402,1,1017060037000,27.59705,-99.47217,0.00,000,0GREC,272,1005402,1,1017060038000,27.59705,-99.47217,0.00,000,0GREC,272,1005402,1,1017060039000,27.59705,-99.47217,0.00,000,0GREC,272,1005402,1,1017060040000,27.59705,-99.47217,0.00,000,0GREC,272,1005402,1,1017060041000,27.59705,-99.47217,0.00,000,0GREC,272,1005402,1,1017060042000,27.59705,-99.47217,0.00,000,0GREC,272,1005402,1,1017060043000,27.59705,-99.47218,0.00,000,0GREC,272,1005402,1,1017060044000,27.59705,-99.47218,0.00,000,0GREC,272,1005402,1,1017060045000,27.59707,-99.47218,0.00,000,0GREC,272,1005402,1,1017060046000,27.59707,-99.47218,0.00,000,0GREC,272,1005402,1,1017060047000,27.59707,-99.47218,0.00,000,0GREC,272,1005402,1,1017060048000,27.59707,-99.47218,0.00,000,0GREC,272,1005402,1,1017060049000,27.59707,-99.47220,0.00,000,0GREC,272,1005402,1,1017060050000,27.59707,-99.47220,0.00,000,0GREC,272,1005402,1,1017060051000,27.59707,-99.47220,0.00,000,0GREC,272,1005402,1,1017060052000,27.59707,-99.47220,0.00,000,0GREC,272,1005402,1,1017060053000,27.59707,-99.47220,0.00,000,0GREC,272,1005402,1,1017060054000,27.59707,-99.47220,0.00,000,0GREC,272,1005402,1,1017060055000,27.59707,-99.47220,0.00,000,0Sample Processed GPS Stream

Click button, navigate to appropriate input files, and selectClick button, navigate to directory containing pre-processed GPS streams and selectLeave blank to use default algorithm parametersClick to run the trip detection after providing all inputsProvide file name to store the derived travel diariesBasic Analysis

Basic Analysis: Results

Enhanced AnalysisClick button, navigate to appropriate input files, and selectAdditional inputs for enhanced analysisProgress bar

Enhanced Analysis: Results

Querying and Aggregation: OptionsAggregation criteriaFiltering criteriaInput: a file containing derived travel diaries

Querying and Aggregation: ResultsOverall aggregation summary

Querying and Aggregation: ResultsTrip table and inter-zonal performance measures (over entire day and all trip purposes)

Querying and Aggregation: ResultsTrip table and inter-zonal performance measures (PM peak, all trip purposes)

Querying and Aggregation: ResultsTrip table and inter-zonal performance measures (entire day, home-based work trips)

Thank You!

Structure of GPRMC Streams

Structure of GeoLogger Streams

Algorithm Parameters

Accept inputsRead in data for first/next vehicleScan GPS stream until a potential trip is detectedCompute trip characteristicsPerform reasonableness checksCheck if end of GPS stream is reached for the current vehicleWrite trip to output fileCheck if there are any more vehicles in the databasePotential trip passes checksPotential trip fails checksYesYesNoTrip diary extraction completeNoConceptual Overview of Process Module

Attributes Characterizing Each Trip in the Derived Travel Diary Database

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