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Supplementing Census Data SANDAG Case Study. DEMOGRAPHIC DATA

Dec 27, 2015

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  • Supplementing Census DataSANDAG Case Study

  • DEMOGRAPHIC DATA

  • Dwelling Unit CountsCensus (SF1)Resolution:Blocks (25,700)

    Property Record Files Resolution:Parcels (800,000)

    Aerial Photographs Resolution:Individual buildingLimitations:Small areas only Buildings, not units

  • Structure TypeCensus (SF3)Resolution:Block groups (2,200)Limitations:Self-reported

    Property Record FilesResolution:Parcels (800,000)

    Aerial Photographs Resolution:Individual buildingLimitations:Small areas only Selected structure types

  • Employment EstimatesCensus (CTPP)Resolution:CTPP zones (500)

    ES202 Files Resolution:Individual employersLimitations:Confidentiality issuesMissing employersMultiple Sites

    Derived from Building Floor AreaResolution:Parcels (800,000)

  • Household IncomeCensus (SF3)Resolution:Block groups (2,200)

    State Income Tax Returns Resolution:Tracts (600)Limitations:Confidentiality issues Definitional differences Complex process

  • Case StudyParcel Level Dwelling Units

  • MGRA Geography

  • Irregular Geography

  • Transit Access

  • Parcel and MGRA Geography

  • Block Group Check

  • Block Counts and Land Use

  • Residential Buildings

  • Problem AreasCensus Structure typesGeo-coding qualityBlock definitionsSenior housing

    Property Record Files Units on public/non-taxable land

    Both Units under construction

  • TRANSPORTATION DATA

  • Number of VehiclesCensus (SF3)Resolution:Block groups (2,200)

    Department of Motor Vehicles Resolution:Countywide

    Home Interview Surveys Resolution:Large summary areasLimitations:Sample bias

  • Average Trip Length (Minutes)Census (CTPP)Resolution:CTPP zones (500)Limitations:Self-reported

    Speed Surveys/Transportation Models Resolution:TAZs (4,600)

    Home Interview Surveys Resolution:Large summary areasLimitations:Sample bias

  • Transit Mode SharesCensus (CTPP)Resolution:CTPP zones (500)

    Transit On-Board Surveys Resolution:Small summary areas

    Home Interview Surveys Resolution:Very large summary areasLimitations:Sample bias

  • Trip TablesCensus (CTPP)Resolution:CTPP zones (500)

    Home Interview Surveys Resolution:Very large summary areasLimitations:Sample bias

  • Case StudyAuto Travel Times

  • Travel Time Surveys

  • California Statewide Travel Survey1,200 San Diego County Households180 Households with GPS-Equipped Vehicles 1,000 GPS trips out of 4,700 total survey tripsFebruary-October 2001GeoStats

  • GPS Coverage

  • GPS Points

  • Freeway Speed Comparison

    Chart5

    63.308673858658.0405311584

    53.288021087640.6616287231

    50.780540466339.8915405273

    GPS

    Model

    Time Period

    Speed (MPH)

    avgspdcomparisonfwynonfwy

    periodfreeway/surfaceGPSModelspddiff

    1163.3158.045.27Off-Peak

    2153.2940.6612.63AM Peak

    3150.7839.8910.89PM Peak

    GPSModel

    11026.2522.733.52Off-Peak

    21026.2822.084.21AM Peak

    31023.7421.622.12PM Peak

    &A

    Page &P

    avgspdcomparisonfwynonfwy

    GPS

    Model

    Time Period

    Speed (MPH)

    GPS

    Model

    Time Period

    Speed (MPH)

  • Arterial Speed Comparison

    Chart4

    26.251111984322.7338523865

    26.281166076722.0759449005

    23.73724746721.6212787628

    GPS

    Model

    Time Period

    Speed (MPH)

    avgspdcomparisonfwynonfwy

    periodfreeway/surfaceGPSModelspddiff

    1163.3158.045.27Off-Peak

    2153.2940.6612.63AM Peak

    3150.7839.8910.89PM Peak

    GPSModel

    11026.2522.733.52Off-Peak

    21026.2822.084.21AM Peak

    31023.7421.622.12PM Peak

    &A

    Page &P

    avgspdcomparisonfwynonfwy

    GPS

    Model

    Time Period

    Speed (MPH)

    GPS

    Model

    Time Period

    Speed (MPH)

  • CTPP Model Comparison

    -4%-11%-7%

    Chart4

    23.422.5

    1311.6

    33.333333333330.9333333333

    CTPP

    Model

    Chart1

    23.422.5

    1311.6

    33.333333333330.9333333333

    CTPP

    Model

    Chart2

    23.422.5

    1311.6

    33.333333333330.9333333333

    CTPP

    Model

    Sheet1

    MinutesMilesSpeed

    CTPP23.413.033.3

    Model22.511.630.9

    -0.0384615385-0.1076923077-0.072

    Sheet1

    CTPP

    Model

    Sheet2

    Sheet3

  • Modeled Travel Times Minutes to CBD by Auto

  • CTPP Travel TimesMinutes to CBD by Auto

  • Modeled Travel Times Minutes to Suburb by Auto

  • CTPP Travel TimesMinutes to Suburb by Auto

  • Supplementing Census DataSANDAG Case Study

    The traffic analysis zone system initially developed for the urban area of Tijuana was expanded to include the rural areas of the Municipality, and also to incorporate Tecate and Playas de Rosarito and the urban area of Ensenada.

    The traffic analysis zone system initially developed for the urban area of Tijuana was expanded to include the rural areas of the Municipality, and also to incorporate Tecate and Playas de Rosarito and the urban area of Ensenada.

    The traffic analysis zone system initially developed for the urban area of Tijuana was expanded to include the rural areas of the Municipality, and also to incorporate Tecate and Playas de Rosarito and the urban area of Ensenada.

    The traffic analysis zone system initially developed for the urban area of Tijuana was expanded to include the rural areas of the Municipality, and also to incorporate Tecate and Playas de Rosarito and the urban area of Ensenada.