Potential pollutant emission effects of connected and automated vehicles
in a mixed traffic flow context for different road types
Abstract
The environmental impact of connected and autonomous vehicles (CAVs) is
still uncertain. Little is known about how CAVs operational behavior
influences the environmental performance of network traffic, including
conventional vehicles (CVs). In this paper, a microscopic traffic and
emission modeling platform was applied to simulate CAVs operation in
Motorway, Rural, and Urban road sections of a medium-sized European
city, assuming different configurations of the car-following model
parameters associated with a pre-determined or cooperative adaptative
behavior of the CAVs. The main contribution is to evaluate the impact of
the CAVs operation on the distribution of accelerations, Vehicle
Specific Power (VSP) modal distribution, carbon dioxide (CO2) and
nitrogen oxides (NOx) emissions for different road types and Market
Penetration Rates (MPR). Results suggest CAVs operational behavior can
affect CVs environmental performance either positively or negatively,
depending on the driving settings and road type. It was found
network-wide CO2 varies between savings of 18% and an increase of 4%,
depending on the road type and MPR. CAVs adjusted driving settings
allowed minimization of system NOx up to 13-23% for MPR ranging between
10 and 90%. These findings may support policymakers and traffic
planners in developing strategies to better accommodate CAVs in a
sustainable way.