In 2022, the United States Department of Transportation adopted a Safe System Approach as the guiding paradigm to address roadway safety. It recognizes that people make mistakes, and the road system should be designed to forgive those mistakes. This is especially true for wrong-way driving prevention – we must do something before people drive the wrong way.
Wrong-way driving is a serious issue that can cause severe crashes. Unlike the cross median crash, a wrong-way crash is defined as a driver entering a roadway through an intersection or ramp terminal and driving in the opposite direction, which could result in head-on collisions. Unfortunately, most drivers haven’t been trained to deal with this situation, whether driving the wrong way themselves or encountering someone driving the wrong way toward them. In such a situation, the reaction time to avoid a crash is relatively short due to the high speeds of the two cars. In the United States, wrong-way driving crashes take approximately 360 lives per year, and the trend is not slowing down.
Wrong-way driving can occur on any roadway, from rural highways to urban arterials. It is hard to trace the origin since a wrong-way driving incident could result in a crash several miles from the initial wrong-way entry point. Especially during nighttime driving, the wrong-way driver won’t realize he or she is driving in the opposite direction due to low traffic flow. As a result, the crash location recorded by the crash report may not help identify problematic sites that need improvements to prevent wrong-way entries. To reduce wrong-way driving crashes, the initial wrong-way entry points must be evaluated for application of countermeasures that can help to prevent vehicles from entering the wrong way. However, unlike crash data, wrong-way entry data is always limited. Most sites with the risk of wrong-way entry remain unnoticed until a severe crash happens.
During my research period at Auburn University, one of my major tasks was finding the ramp terminals with the greatest risk for vehicles entering the wrong way. We found that wrong-way driving actually happens much more frequently than we expected. As a driver, we may rarely see one case of wrong-way driving in our lifetime, but as researchers studying interchange terminals over a prolonged period of time, we found more than 15 wrong-way entries per day at some locations. The wrong-way driving incidents happen during daytime and nighttime, not only by passenger vehicles but also by commercial trucks.
Based on my monitoring, most of the wrong-way drivers could conduct self-correction pretty fast, but around 9% of them will enter the interstate highway regardless of the existence of wrong-way signs on the ramp. Our research focused on identifying what kind of ramp terminals could cause drivers to enter the wrong way. By analyzing the characteristics of all the ramp terminals with confirmed wrong-way entries, we developed a mathematical model to find similar locations. We believe wrong-way driving could also happen at those locations if they have similar characteristics.
Sain Associates is helping the Tennessee Department of Transportation (TDOT) develop a Wrong Way Driving Prevention Plan using low cost countermeasures. To investigate the potential wrong-way entry point and the existing wrong-way countermeasures, we specially designed a site-visit checklist and conducted site visits for all the interchange terminals in Regions 3 and 4. After all of the field reviews, we developed a Systemic Wrong Way Driving Prevention Plan and provided a detailed recommendation drawing for each ramp terminal. We reviewed the wrong-way driving crash data during the past three years and evaluated the risk of wrong-way driving entry at each partial cloverleaf interchange within the study area to find the high-risk locations for higher-tier improvement. We expect a significant reduction in wrong-way driving upon implementing this project and continue to work towards Vision Zero.