The Automated Data Collection (ADC) & Processing section polls, processes and evaluates traffic data from 159 sites where data is collected continuously. Depending on the type of sensors installed at each site traffic data recorded and collected could include volume, classification (number of axles and spacing and/or length of vehicle), weight and/or speed information. These sites provide a detailed picture of the traffic volumes throughout the entire year, and provide the most reliable estimates of Annual Average Daily Traffic (AADT). PTR sites provide the traffic statistics and trends used to develop estimates of AADT from short duration traffic counts. Vehicle classification reporting normally consists of four classes of vehicles and relate to passenger cars/light trucks, single unit trucks, double unit trucks, and triple unit trucks. Our current equipment collects vehicle classification in 13-bins or categories ("bins" are vehicle categories using Federal Highway Administration (FHWA) criteria with bin 1 being motorcycles, bin 2 cars and the final bin 13 being trucks with seven or more axles and multiple trailers).
The 159 Permanent Traffic Recorder (PTR) sites are comprised of:
101 Permanent Traffic Recorder (PTR) sites, 37 weigh-in-Motion (WIM) sites,18 Strategic Highway Research Program (SHRP)/Long Term Pavement Performance (LTPP) sites and 3 volume recorders.
The TDO also collects, analyzes and reports on 15 Northwest Region (Seattle Area) Traffic Systems Management Center sites.
Questions or comments regarding the Automated Data Collection's products and services, please Email the Automated Data Collection & Processing Section or call by phone at (360) 570-2392.
