Field Experiment of Connected Vehicle Applications to Improve Mobility and Safety in Phoenix

Abstract: Emerging technologies, particularly connected vehicles (CVs), offer promising solutions to address the challenges of traffic mobility and safety. While connected vehicles have demonstrated theoretical improvements in traffic flow, their real-world effectiveness in urban areas remains unclear. Therefore, based on a recent field experiment conducted by the City of Phoenix (COP) for emergency vehicle preemption, the potential impacts of CVs on traffic mobility and safety are evaluated. To measure the impact of connected vehicle technology, a corridor with seven functional Roadside Units (RSUs) in Ahwatukee was selected for testing due to its high traffic volume and critical location. While emergency vehicles may have a more significant impact on traffic due to sirens and vehicle yielding, a regular vehicle equipped with an Onboard Unit (OBU) is used for preliminary testing under both activated and deactivated preemption conditions. The preliminary findings indicate that connected vehicle technologies significantly reduce travel time and delays across all periods, highlighting their potential to improve traffic efficiency. Specifically, travel time decreased by 21.10% during the AM peak, 19.85% at midday, and 6.09% during the PM peak. Delays were also significantly reduced, with a 59.84% reduction in the AM peak, a 46.95% reduction at midday, and a 16.06% reduction in the PM peak. These results demonstrate the promising role of connected vehicle technology in improving response times and reducing delays. To fully realize the potential of connected vehicle technology, additional mobility and safety applications, such as transit signal priority, curve speed warnings, and spot weather warnings, stand ready for testing. These applications further enhance traffic flow, safety, and emergency response efficiency in urban areas like Phoenix.