GlidePath: Eco-Friendly Automated Approach and Departure at Signalized Intersections

Recently, there has been significant research on environment-focused connected vehicle (CV) applications that involve determining optimal speed profiles for vehicles traveling through signalized intersections and conveying this information to drivers via driver-vehicle interfaces (DVI's). However, findings from previous studies indicate that drivers may not be able to precisely follow the recommended speed profiles, resulting in degraded effectiveness of the applications. Moreover, the DVI could be distracting, which may compromise safety. As an alternative, partial automation can play an important role in ensuring that the benefits of these CV applications are fully realized. In this study, a partially automated vehicle system with an eco-approach and departure feature (called the GlidePath Prototype), which can receive dedicated short range communication message sets from the intersection and automatically follow recommended speed profiles, was developed, demonstrated, and evaluated. The results revealed that compared to manually following the recommended speed profiles, the GlidePath Prototype reduced fuel consumption by 17% on average. In some cases, the fuel savings are greater than 40% while the travel time is shortened by up to 64%. Furthermore, the system potentially improved the driving comfort since it would smooth out the speed profiles.