Abstract
The Advanced Crash Avoidance Technologies (ACAT) program initiated by the National Highway Traffic Safety Administration had two major overall objectives. These were to develop a standardized Safety Impact Methodology (SIM) tool to evaluate the effectiveness of advanced technologies in avoiding and mitigating specific types of vehicle crashes; and to develop and demonstrate objective tests that are used in the SIM to verify the safety impact of a real system. The developed SIM applies computer simulations of the driver-vehicle-environment, involving time-space relationships between the subject vehicle and a collision partner, and predicts crash, injury and fatality outcomes, with and without the Advanced Collision Avoidance Technology countermeasure, for a sample of NASS/CDS cases; and a systems model to extend the sample results to the national level, in order to estimate effectiveness and safety benefits of the countermeasure. Objective tests were developed to ensure that the proposed safety problem countermeasure meets full system performance specifications and that the results are directly linked to the safety needs and a sample of technology-relevant accidents being addressed. Results from the objective tests were used to parameterize, calibrate and validate the SIM tool, which was then used to estimate US-level safety benefits.
An example application of the developed SIM tool and related objective tests were used to evaluate a prototype Advanced Collision Mitigation Braking System (A-CMBS) in the first phase of the program. A-CMBS is undergoing development and refinement, as the next step in the evolution of the production Collision Mitigation Braking System (CMBS).
During the second phase of the program, the SIM tool was further extended, refined, and applied to another advanced collision avoidance technology to verify its applicability to wider range of advanced safety technologies and crash types. An example technology was a pre-production Head-on Collision Avoidance Assistance System (H-CAAS), which is intended to detect, warn and mitigate specific crash types, including a severe, primary crash type in which the subject vehicle drifts laterally into the path of an on-coming vehicle, typically as a result of driver inattention.
Keywords: Safety Effectiveness, Simulation