Impacts of connected and automated vehicles on freeway with increased speed limit

Abstract

As a revolutionary technology, Connected and Automated Vehicles (CAVs) have great potential to reduce traffic collisions, increase transportation system performance, and improve environmental sustainability. This research aims to investigate the benefit or trade-off of CAVs on freeway capability, fuel consumption, and emission. To fulfil this goal, the open-source traffic simulation software, SUMO was used to model CAV fleets. This study conducted a sensitivity analysis on three variables, i.e., CAV penetration, CAV time headway, and freeway speed limit. As expected, the simulation results justified that the shorter the time headway is, the higher maximum flow can be achieved. Higher speed limit contributes to a faster free-flow speed and a more substantial road capacity. While at the same time, it weakens the stability of the flow. From the perspective of fuel economy and environment, a recommended optimal time headway must be found.