The objective of this study was to gain an insight into the effects of the introduction of Autonomous Intelligent Cruise Control (AICC) on traffic performance and safety on motorways. The MICroscopic model for Simulation of Intelligent Cruise control (MIXIC) was used. The study has confirmed the notion from earlier studies that AICC systems can contribute to a more stable traffic flow without sacrificing capacity. The results regarding traffic performance were: (1) a (very small) increase in travel time; (2) a decrease in the standard travel time deviation; (3) a small decrease in the average speed; and (4) a decrease in the standard speed deviation. These results were found for AICC penetration levels on passenger cars of 20% (target headway 1.0 and 1.5) and 40% (target headway 1.0). However, for 40% penetration and a target headway of 1.5 a deterioration of the traffic performance was found at the higher traffic demand levels. Concerning traffic safety the following results were obtained: (a) a decrease in the number of shockwaves and in the number of vehicles in a shockwave; (b) an increase in Time-To-Collisions (TTCs), especially for AICC vehicles; (c) a decrease of headways, especially on the left lane; and (d) a slight increase of the fraction of headways less than 0.5 s. These results pertain to all penetration levels and AICC target headways. The overall AICC impacts on traffic safety are not obvious. (A)
Abstract