Quantifying Impacts of Connected and Automated Vehicles on Traffic Operation of a Diamond Interchange in UAE Using Micro-simulation

Connected and Automated Vehicles (CAVs) are expected to dominate our future mobility. CAVs have potential benefits for improving traffic operations and safety for all road users, reducing traffic congestion, vehicle emissions, fuel consumption, and smoothening traffic flow. Since CAVs are still on a very narrow level of implementation worldwide, their impact on traffic flow is still under investigation. Traffic simulation tools have been frequently utilized to collect more insights and clarify uncertainties associated with CAVs implementation. Many studies have investigated CAVs at the segment level; however, exploring CAVs' impact at the network level has not been conducted widely. This study aims to quantify the impacts of CAVs on the traffic operation of a diamond interchange in Abu Dhabi City, UAE, by utilizing a widely-used micro-simulation tool, namely PTV VISSIM. The performance of multiple scenarios was analyzed in terms of both traffic operations and environmental emissions, specifically average speed, average delay, and produced emissions. Moreover, the simulation was performed for different Market Penetration Rates (MPRs), starting from 0% (representing no CAVs) up to 100% (full CAVs) with an increment of 10%. Each scenario was run at three different traffic congestion levels: uncongested with a 0.8 volume-to-capacity (V/C) ratio, moderate congestion with a V/C ratio of 1, and over-congested with a V/C ratio of 1.2. Results showed that the average delay and the average speed had undergone an improvement of 15.5% and 9.66%, respectively, at 100% MPR and over-congestion level (V/C ratio =1.2). Furthermore, GHG emissions were found to be reduced by 9.6%. Moreover, it was revealed that CAVs would have a more significant role in arterial roads than freeways because of the aggressive driving behavior in arterial road driving nature.