Section 3: Automatic Traffic Recorder Volume Data
Anchor: #i1104837ATR Data Collection
TPP collects traffic data using permanent automatic traffic recorder (ATR) equipment at approximately 160 permanent sites (see Table 1-1) around the state. (To see a map of TxDOT districts, link to http://www.dot. state.tx.us/local_information/default.htm.) ATR locations are selected by TPP and TxDOT districts in accordance with the FHWA Traffic Monitoring Guide (TMG) (link to http://www.fhwa.dot.gov/ egsregs/directives/fapg/cfr050b.htm) and approved and implemented by TPP.
The ATRs collect data 24 hours a day, 365 days annually, for each lane. The equipment records traffic volumes as total and as directional traffic for each station. TPP retrieves the data via modem daily, Monday through Sunday, to develop seasonal factors and estimate vehicle miles of travel (VMT)
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Anchor: #i1104864
ATR Data Analysis
TPP analyzes hourly volumes and daily totals using historical patterns for controls. Seasonal variation factors developed by TPP are applied to accumulative count recorder (ACR) axle counts to develop average annual daily traffic (AADT) figures. Statewide VMT is estimated from these data. TPP also derives directional factors and K-factors from the data collected at each ATR site.
Anchor: #BGBJGBJIATR Data Reporting
TPP prepares monthly reports for each site. Monthly reports provide the actual hourly counts and a percent variation in traffic for each ATR site. Access to monthly reports is made via the DOTS mainframe. The year-end report contains more detailed information including annual average hourly volumes by days of the week, highest hours of the year, average daily traffic by month, day and season, AADT percent variation by years, and AADT by year for each site. TPP produces annual reports in Excel format.