Improving Access and Management of Public Transit ITS Data (2022) / Chapter Skim
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Pages 46-54
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When updated versions of ITS data are provided to transit agencies, agencies should process this data using the tools described in this report, including the Format Validation, Data Quality, and Data Transfer Tools (if using)
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To integrate GTFS and with the ITS data structure, identifiers should be kept as consistent as possible between schedule periods to enable easy analysis across periods. For example, when trip start times are shifted only slightly from one version of a timetable or schedule to the next version of a timetable or schedule, but no trips are added to the timetable, maintaining the same trip_id allows for easy aggregation and comparisons across schedule periods.
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6.4.3 Designating Start and End of a Trip One of the most consistent data quality issues with AVL and APC systems is detecting each trip's correct start and end. Resolving this issue is important for correctly assigning data records to trips within the data structure.
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Agencies will need to convert scheduled times from GTFS from the HH:MM:SS format to POSIX time for integration in the data structure. If desired, agencies can maintain additional time fields using the HH:MM:SS format for readability.
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6.8.2 Trains and Other Vehicles That Reverse Direction Since trains frequently stop at a destination to complete a trip, then reverse direction to begin a new trip, the same train consist may be used with a different order of component cars. Records in the Train_cars file representing individual train cars are associated with vehicles (train consists)
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Similarly, if a transit agency standardly collects vehicle-level revenue, the agency could add a vehicle-based file that is similar to the Station_activities file to track revenue collected by each vehicle over exclusive time periods. 6.8.5 Boardings and Alighting Associated with a Specific Train Car As described in Section 3.2.1, some transit agencies may desire to track boardings by train car, in particular, to measure crowding along a rail platform.
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52 Improving Access and Management of Public Transit ITS Data reliable data sample at the trip level across a single month of sampling, but to produce a reliable result at the timepoint level, the sample must extend across a 3-month period. Clearly defining the sample period and number of observations required for each data type and each level of aggregation is critical to appropriate application of data in planning processes.
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TRB Transportation Research Board TSA Transportation Security Administration U.S. DOT United States Department of Transportation
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Transportation Research Board 500 Fifth Street, NW Washington, DC 20001 ADDRESS SERVICE REQUESTED ISBN 978-0-309-68745-4 9 7 8 0 3 0 9 6 8 7 4 5 4 9 0 0 0 0
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