The introduction of driver support systems, such as (Autonomous) Intelligent Cruise Control, is foreseen within a few years. However, it is still uncertain how these systems will affect traffic flow characteristics on motorways. A simulation study has been conducted to assess the impacts on road capacity more precisely. Ten different Intelligent Cruise Control designs are investigated, and compared with the reference situation without such support systems. The equipment penetration rate of the systems studied varied from 10%, 20%, 50% to 100%. A capacity analysis was performed for a common bottle-neck situation: an on-ramp to a two-lane motorway. Based on the simulation results, some unexpected findings emerged. Support systems which support the driver at all speeds and without restricted deceleration level give rise to capacity gains of more than 12%. Expected 'normal'-ICC systems will hardly increase traffic flow performance. A special stop-and-go AICC design did not improve the traffic flow quality. It was found that a headway setting of 1.2 s regardless the AICC type will not change road capacity near an on-ramp bottle-neck significantly. Conclusions based on these findings: capacity impact of such driver support systems will be very limited. For the covering abstract see IRRD E102946.
Abstract