The Annual Average Daily Traffic Counts (AADT) are collected by Texas Department of Transportation (TxDOT) and comprise the “On System” roadways defined as major highways and regionally significant arterials. The AADT counts result from a mathematical computation where the counts are made over a given period of time. The counts are done during the non-summer weeks; excluding Fridays, Saturdays, Sundays, and holidays. The AADT counts are what could be expected during a normal workday of a given week. For tables and maps of counts prior to 2008 please put in a request.
The City of Austin (COA) collects vehicle volume counts on an “as needed basis.” When a particular location needs a traffic study COA adds these counts to the City of Austin Traffic Counts spreadsheet. COA does studies to set the speed limit on new streets and to determine the need for school zones at various locations. The city does not collect any data on major highways within Austin. The method COA uses to collect the counts is the rubber tube stretched across the road that attaches to a traffic counter.
The approximately 3,500 Saturation Counts are collected by Texas Department of Transportation (TxDOT) and comprise “Off System” roadways such as arterials and local streets not included in the AADT “On System” counts. Saturation counts are done periodically on a regional basis and the time frame will vary by region.
Other local sources of traffic counts: