Analysis of Traffic Flow With Mixed Manual and Intelligent Cruise Control Vehicles: Theory and Experiments

During the last decade considerable research and development efforts have been devotedto automating vehicles in an effort to improve safety and efficiency of vehicular traffic.While dedicated highways with fully automated vehicles is a future objective, theintroduction of Intelligent Cruise Control (ICC) vehicles on current highways designed tooperate with manually driven vehicles is a realistic near term objective. The purpose ofthis report is to analyze the effects on traffic flow characteristics and environment whenICC vehicles with automatic vehicle following capability (in the same lane) operatetogether with manually driven vehicles. We have shown that ICC vehicles do notcontribute to the slinky effect phenomenon observed in today’s highway traffic when thelead manual vehicle performs smooth acceleration maneuvers. We have demonstratedthat ICC vehicles help smooth traffic flow by filtering the response of rapidlyaccelerating lead vehicles. The accurate speed tracking and the smooth response of theICC vehicles designed for passenger comfort reduces fuel consumption and levels ofpollutants of following vehicles. This reduction is significant when the lead manualvehicle performs rapid acceleration maneuvers. We have demonstrated using simulationsthat the fuel consumption and pollution levels present in manual traffic simulated using acar following model that models the slinky effect behavior observed in manual drivingcan be reduced during rapid acceleration transients by 28.5% and 1.5%-60.6%respectively due to the presence of 10% ICC vehicles. These environmental benefits areobtained without any adverse effects on the traffic flow rates. Experiments with actualvehicles are used to validate the theoretical and simulation results.