Evaluation of A Truck In-Cab Alert System

About the report:

Transportation agencies have long communicated directly with truck drivers regarding weigh station compliance and parking availability, sometimes making use of applications provided by private third-party partners. One of these applications has expanded capabilities that allow agencies to transmit safety alerts directly to drivers through the in-cab electronic logging device systems. In December 2022, VDOT partnered with one of these providers to issue emergency weather-related restrictions and congestion alerts directly to drivers via push notifications directly on the in-cab electronic logging devices (ELDs) or smartphone devices running the in-cab alert app. This project studied the characteristics of the in-cab alerts in terms of coverage and scope, estimated market penetration, and observable effects on driver behavior from GPS traces.

The results suggest that in-cab alerts from an evaluated system reach 6–12% of commercial vehicles across Virginia’s interstate corridors, with congestion alerts typically notifying 2–7 trucks per event while dangerous slowdown (DSD) alerts notify 1–2 trucks. Analysis of vehicle trajectories shows that over 91% of trucks maintain their initial speed in the first 10 seconds after receiving an alert, with speed reductions becoming more pronounced over time. Speed response varies significantly based on initial conditions, with trucks traveling at lower initial speeds (50–55 mph) more frequently reducing their speed compared to those at higher speeds. While this behavior suggests a greater likelihood of speed reduction in denser traffic conditions, it is unclear whether this is directly due to the alert itself or influenced by prevailing traffic speeds.

Large carriers report successful integration of in-cab alerts with other safety technologies, though the system’s greatest potential may lie in reaching smaller carriers without advanced driver assistance systems. With eleven state agencies now using the system and showing positive results despite modest penetration rates, VDOT should continue providing these alerts while exploring partnerships with other states to reduce costs. Economic analysis indicates the program costs would be justified by preventing just one injury crash every 17 months.

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