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This paper presents recent results of on-going research to build new maps of driver performance in car-following situations. The novel performance map is comprised of four driving states: low risk, conflict, near crash, and crash imminent - which correspond to advisory warning, crash imminent warning, and crash mitigation countermeasures. The paper addresses two questions dealing with the approach to quantify the boundaries between the driving states: (1) Do the quantified boundaries strongly depend on the dynamic scenario encountered in the driving environment? and (2) Do the quantified boundaries vary between steering and braking driver responses? Specifically, braking and steering driver performances are examined in two car-following scenarios: lead vehicle stopped and lead vehicle moving at lower constant speed.

This paper describes the safety evaluation results from a Field Operational Test (FOT) of an Intelligent Cruise Control (ICC) system. The primary goal of this evaluation was to determine safety effects of the ICC system. Safety surrogate measures were established and examined for normal driving situations as well as for safety–critical situations. It was found that use of the ICC system in the FOT was generally associated with safer driving compared to manual control and is projected to result in net safety benefits if widely deployed.

This paper describes the concept of using state space boundaries to evaluate the safety effects of longitudinal collision avoidance systems from data produced in field operational tests. The boundaries are represented in terms of the relative range and range rate between a lead vehicle and the vehicle hosting the collision avoidance system. Phase plane diagrams are used to illustrate the state space boundaries. Parameters of curves representing the boundaries were selected such that the boundaries would be fairly well distributed over the range vs. range-rate space with the ones closer to the horizontal axis (range = 0) being indicative of a relatively higher hazard potential. The application of these state space boundaries is examined with data available from a recently completed field operational test sponsored by the National Highway Traffic Safety Administration.