Quantifying air quality benefits resulting from few autonomous vehicles stabilizing traffic

Abstract

It is anticipated that in the near future, the penetration rate of vehicles with some autonomous capabilities (e.g., adaptive cruise control, lane following, full automation, etc.) will increase on roadways. This work investigates the potential reduction of vehicular emissions caused by the whole traffic stream, when a small number of autonomous vehicles (e.g., 5% of the vehicle fleet) are designed to stabilize the traffic flow and dampen stop-and-go waves. To demonstrate this, vehicle velocity and acceleration data are collected from a series of field experiments that use a single autonomous-capable vehicle to dampen traffic waves on a circular ring road with 20 to 21 human-piloted vehicles. From the experimental data, vehicle emissions (hydrocarbons, carbon monoxide, carbon dioxide, and nitrogen oxides) are estimated using the MOVES emissions model. This work finds that vehicle emissions of the entire fleet may be reduced by between 15% (for carbon dioxide) and 73% (for nitrogen oxides) when stop-andgo waves are reduced or eliminated by the dampening action of the autonomous vehicle in the flow of human drivers. This is possible if a small fraction (∼5%) of vehicles are autonomous and designed to actively dampen traffic waves. However, these reductions in emissions apply

Ecological traffic management: A review of the modeling and control strategies for improving environmental sustainability of road transportation

“…They also induce a smoother driving and fewer braking events. But the results presented in Stern et al (2019) hold for situations with traffic waves only.…”

“…Typically, this corresponds to the injection of some autonomous vehicles in the traffic flow with the objective of stabilizing it. Stern et al (2019) present how this method can reduce the emissions of the whole traffic by dampening stop-and-go waves. To validate this approach, the authors present the results of field experiments in which vehicle velocity and acceleration data are collected.…”

Connectivity and Automation as Enablers for Energy-Efficient Driving and Road Traffic Management

“…Di Vaio et al (2019) confirm the robustness and the efficiency of such approaches to dampen down traffic waves, while also considering delays due to V2V communication. Stern et al (2019) propose to quantify the potential benefits of traffic stabilization by realizing field experiments with 20 to 21 HVs and 1 CAV (∼ 5% of the vehicle fleet) traveling along a circular ring road, as represented in Fig. 10.…”

Potential Effects of Automated Vehicles on Road Transportation: A Literature Review

“…In a recent study, Stern et al (2019) investigated the effects of AVs on emissions on a single-lane roadway during stop-and-go traffic wave. The authors pointed out that AVs can reduce vehicle emissions even at lower market penetration rates due to smoother traffic flow resulted from their potential to deter traffic waves.…”