Cooperative Eco-Driving at Signalized Intersections in a Partially Connected and Automated Vehicle Environment
The study described a Cooperative Eco-Driving (CED) system targeted for signalized corridors, focusing on how the penetration rate of Connected and Automated Vehicles (CAV) affects the energy efficiency of the traffic network on a 6-mile corridor with two signalized intersections along the University Avenue in Riverside, California. The study defined two different types of vehicles in the system as conventional vehicles and CED vehicles, with different role transition protocols and longitudinal control models for each, based on their degrees of connectivity and automation.
A microscopic traffic simulation evaluation was conducted using PTV VISSIM with realistic traffic flow and signal timing data collected during 7:00-8:00 AM on Thursday, June2, 2016 for the City of Riverside provided by the government. The effects on traffic mobility were evaluated, and the environmental benefits were analyzed by the U.S. Environmental Protection Agency’s MOtor Vehicle Emission Simulator (MOVES) model. In the study, conventional vehicles were assumed to be driven by human drivers, which were not equipped with any on-board sensor, therefore, the Wiedemann car-following model was used to model the longitudinal behaviors of conventional vehicles. CED vehicles were separated into two different components: the CED vehicle longitudinal control model that delivers reference values of vehicle acceleration, and a vehicle powertrain model that transforms reference acceleration values into realized throttle or brake values. Specifically, eco-approach and departure (EAD) maneuvers were also tested with EAD-Only vehicles drive in an ego manner.
- Positive impacts on NOX, HC and CO were observed at all observed penetration rates of CED vehicles in the traffic system.
- 3.9 percent reduction on energy consumption was observed when there were 80 percent CED vehicles.
- When all vehicles were CED vehicles, 7.1 percent and 2.5 percent reduction on energy consumption was observed compared to baseline scenario 1 (0% CED & 100% Conventional) and scenario 2 (0% CED and 100% EAD-only).
- Up to 59 percent reduction on pollutant emissions was observed at 100 percent penetration rate of CED vehicles, when compared to the baseline.