Engineering Countermeasures for Red-Light Running: A State-of-the-Art Review

Abstract: Red-light running is a critical safety concern at signalized intersections as it can lead to serious injuries and fatal crashes. According to a FHWA report in 2024, fatalities from red-light running in the U.S. increased by over 30% between 2017 and 2021. According to the Insurance Institute for Highway Safety (2022), the U.S. experienced 1,149 deaths and 107,000 injuries resulting from red-light running (RLR) crashes. Such serious driver behavioral crashes are not limited to the U.S. but are prevalent in many other countries worldwide. Various countermeasures have been developed, implemented, tested, and documented over the years. These measures can be broadly categorized into two main types: engineering countermeasures and enforcement countermeasures. This study focused on reviewing existing literature on engineering countermeasures by classifying them into five categories based on their functionality including improving signal visibility, enhancing the likelihood of stopping, adjusting signal timing parameters, removing the need to stop, and protecting vehicles from dilemma zone conflicts and summarizing relevant studies within those categories. The review indicates that different countermeasures can exhibit a varying range of safety performance under different conditions. Notably, the same countermeasure often yields widely diverse results when tested by different researchers in different settings. The review also revealed that some countermeasures, though claimed highly effective by some researchers, can yield negative results if their implementation does not follow proper guidelines. Among all the evaluated strategies, advanced dilemma zone protection systems, featuring dynamic green and red extension capabilities, have emerged as the most effective technological solutions for mitigating red light running to date.