Enhancing Intersection Safety through Connected Vehicle Technologies: A Case Study of Red-Light Violation Warnings (RLVW)

Signalized intersections are among the most collision-prone environments in the U.S. transportation network. Despite various engineering innovations, red-light running remains a persistent, deadly behavior, causing an estimated 1,100 fatalities and 127,000 injuries annually. Although prior studies have examined red‑light running countermeasures and early Connected Vehicle (CV) safety applications, empirical evidence on real‑world Red‑Light Violation Warning (RLVW) performance remains limited. Existing work is largely simulation‑based or short‑duration testing, leaving a gap in understanding how drivers adjust speed and compliance behavior in operational CV corridors. This study addresses that gap by evaluating whether in‑vehicle RLVW alerts produce measurable speed reductions, whether repeated exposure leads to sustained compliance, and whether effects remain stable across diverse roadway contexts.

This paper analyzes Phase 2 of the Connected Marysville-Dublin Pilot, a pioneering U.S. field study involving 144 vehicles instrumented with on-board units (OBUs) within a CV corridor in Ohio. The Red-Light Violation Warning (RLVW) application utilized Signal Phase and Timing (SPaT) and intersection map (MAP) data from roadside units (RSUs) to alert drivers of impending violations based on speed and trajectory. Using Wilcoxon signed-rank tests for non-parametric speed data, we evaluated driver profiles pre- and post-alert. Findings were consistent: drivers reduced speed by 4.80 to 8.73 mph within 2.5 seconds, and 10.61 to 15.80 mph within 5 seconds. Notably, compliance improved over the study period, suggesting that repeated exposure created a behavioral conditioning effect where drivers internalized the system and modified their approach over time. Disaggregated analysis across sub-corridors confirmed these results despite variations in urban context and geometry, supporting the findings' external validity. Furthermore, 72.7% of surveyed drivers believed CV technology reduces crash frequency and severity, with RLVW alerts identified as a highly valued feature.

These findings suggest that real-time, in-vehicle alerting can produce measurable, sustained improvements in driver compliance. As policymakers navigate broader CV adoption, the intersection emerges as a foundational site for safety infrastructure investment. This work strengthens the empirical case for prioritizing RLVW-capable infrastructure in nationwide safety programs.