Accuracy of Probe-Based Annual Average Daily Traffic (AADT) Estimates in Border Regions

This report documents the results of the study that examined the accuracy of probe--AADT estimates at Texas-Mexico border crossings and on counted roadways that are in proximity to the Mexican borders. In this project, StreetLight Data provided TTI with unscaled and uncalibrated GPS and LBS trip count data for commercial and privately owned vehicles, as well as probe-based AADT estimates for several locations in the two study areas. For each study area, TTI determined the penetration rate of mobile devices and compared StreetLight Data AADT estimates against traffic volume data collected by various state and local agencies in Texas. The findings of this research may apply to other border regions across the United States. This presents an opportunity for technology transfer. In addition, obtaining AADT estimates from probe data could provide a common measure to assess the performance of traffic operations on both sides of border crossings. It could also yield time and cost savings for transportation agencies that either do not collect traffic volume data (e.g., Mexican agencies) or deploy expensive traffic equipment. It could also reduce safety risks to employees and contractors who typically go out in the field to install sensor devices in and on roadways. Further, it can assist agencies in meeting new federal requirements according to which States must have access to a series of Model Inventory Roadway Elements - Fundamental Data Elements, including AADT, for all public paved roads by 2026.