Simulation Study Evaluating Traffic Signal Priority and Commercial Vehicle Platooning at Selected Canadian Intersections Revealed Travel Time Savings and Reduced Number of Vehicle Stops.
Operational Impact of the Through-Traffic Signal Prioritization for Heavy Commercial Vehicle Platooning on Urban Arterials
Heavy Commercial Vehicle (HCV) platooning is one of the applications of Vehicle-to-Vehicle (V2V) technology, with the potential to reduce fuel consumption and emissions. This study investigated the operational impact of Society of Automotive Engineers (SAE) Level 4 (High driving automation) HCV platooning on urban arterials. The study corridor was a major arterial and designated HCV route in Ontario, located northwest of Toronto, which had three lanes in each direction and 16 signalized intersections. A microscopic traffic simulation model of the study corridor was developed to investigate the impact of Traffic Signal Priority (TSP) and low levels (zero, five, and 10 percent) of HCV platooning. Traffic volumes, intersection turning movement counts and corridor travel times were obtained for the 2016 Fall season from September to November to calibrate the microscopic traffic simulation model. The performance measures considered included travel time and the number of stops for all vehicles, passenger vehicles and HCVs.
Five scenarios were developed to investigate the operational impact of Level 4 HCV platooning on urban arterials with existing traffic controls and with the addition of TSP for HCV platoons. These scenarios included multiple tests to analyze various market penetration rates:
- Base model (NP0), representing a do-nothing scenario with no TSP and zero percent HCV platooning,
- Alternative model 1 (NP5), simulating existing traffic controls with no TSP and the truck volume adjusted to include five percent HCV platooning,
- Alternative model 2 (NP10), simulating existing traffic controls with no TSP and the truck volume adjusted to include 10 percent HCV platooning,
- Alternative model 3 (TP5), simulating a TSP system with the truck volume adjusted to include five percent HCV platooning,
- Alternative model 4 (TP10), simulating a TSP system with the truck volume adjusted to include 10 percent HCV platooning.
The study conducted 150 simulations in total with 30 runs completed for each of the five scenarios. The simulation model produced traffic volumes that simulated an hour of real-world traffic volumes at the 95 percent confidence level. The two main measures of effectiveness for calibration were traffic volume and travel time.
- The findings from the study revealed that TSP strategy with 5 to 10 percent of HCV platooning could improve the travel times for all vehicles on the corridor.
- TSP with five percent HCV platooning (Scenario TP5) reduced travel time for all vehicles by 29 seconds per vehicle (3.4 percent reduction from 14.23 mins to 13.75 mins) and decreased the number of stops for all vehicles by 6.4 percent (from 5.18 to 4.85 stops).
- TSP with 10 percent HCV platooning (Scenario TP10), however, reduced travel time for all vehicles by 12 seconds per vehicle (1.4 percent reduction from 14.23 mins to 14.03 mins), and decreased the number of stops for passenger vehicles only, by 2.7 percent (from 5.21 to 5.07 stops).
- The travel time of passenger vehicles decreased by 40 seconds per vehicle with TP5 and by 32 seconds per vehicle with TP10.
HCV travel time was not enhanced by TP10. This implies that HCV platooning with a rate of 10 percent or higher could cause delays, particularly for HCVs, despite the presence of TSP in major intersections of the study corridor.