Calculation Method

TxDOT created the car-space method to calculate the space between cars in 1-mile increments, factoring:

  • Number of lanes
  • Annual average daily traffic (AADT)
  • Percentage of trucks
  • Average car length

The calculated space between cars is categorized to illustrate levels of congestion.

Peak Hour On-System Congestion Maps, Tables and Graphs

Base Year ZIP
2017
2016
2015
Forecast Year ZIP
2037
2036
2035

Divisions