This study used real-world inner-city road network data input into a simulation model to estimate the fuel saving benefits of implementing a traffic-light-to-vehicle communication (TLVC) system. Using short range wireless communications the system was designed to broadcast signal timing information to nearby vehicles enabling them to calculate approach speeds needed to hit green lights and communicate this information to drivers. The objective was to optimize travel speeds and avoid unnecessary braking and acceleration maneuvers.
Vehicle performance was calculated for single and multiple vehicle scenarios "with" and "without" TLVC systems. A microscopic simulation program (VISSIM) was used to represent vehicular traffic, communications from traffic lights to vehicles, and driver behavior subject to a speed-adaption. Impacts on fuel consumption were calculated using a passenger car and heavy duty emissions model (PHEM). The single vehicle scenario represented performance on a roadway segment between traffic lights spaced at approximately 700 meters. For scenarios with multiple vehicles the network represented an inner-city section of Karlsruhe, Germany with 15 signalized intersections.
The findings represented averages for all combinations of penetration rates for radio equipped vehicles, information distances between vehicles and traffic lights, and communication models.
- The simulation of a single vehicle and traffic light indicated that TLVC can reduce fuel consumption up to 22 percent and decreased CO, NOx, and particulate matter emissions up to 80 percent, 35 percent and 18 percent, respectively.
- Suboptimal gear choice, however, voided these benefits. The authors recommended that future applications supplement speed advice with gear shifting advice.
- The network simulation model with multiple vehicles indicated that TLVC can reduce fuel consumption by 8 percent.