Light vehicles that automatically activate in-vehicle alerts, seat belt tensioners, and braking systems can reduce fatalities by 3.7 percent.
US-level analysis of the Honda Advanced Collision Mitigation Braking System (A-CMBS)
Made Public Date


United States

Advanced Crash Avoidance Technologies (ACAT) Program – Final Report of the Honda-DRI Team, Volume I: Executive Summary and Technical Report

Summary Information

This study evaluated the effectiveness of an Advanced Collision Mitigation Braking System (A-CMBS) designed with forward sensing radar, an on-board electronic control unit, and sensors to monitor vehicle speed, brake pressure, steering angle, and yaw to predict and warn drivers of impending collisions, and automatically implement countermeasures to avoid or mitigate collisions.

The system addresses four types of collisions (intersecting path, rear-end/forward impact, head-on, and pedestrian crashes) and provides countermeasures in three stages. Initially, if the system senses a collision is likely within about three seconds, visual and audio alerts are provided to the driver to take action. If a collision is still likely within two seconds, the system provides a tactile warning in the form of a seatbelt tug and begins to automatically apply light breaking force. Finally, if a collision is imminent, the system automatically tightens seatbelts to place the driver in a crash position and applies strong braking to reduce velocity before impact.


Researchers obtained crash data from three U.S. DOT database archives (NASS/CDS, Pedestrian Crash-worthiness Data System (PCDS) and FARS) and analyzed these data to identify crash scenarios where A-CMBS technology would apply. A Safety Impact Methodology (SIM) tool was developed to reconstruct and model technology relevant crash types. Test track and driver simulation experiments were conducted to assess driver response to A-CMBS warnings and interventions using a group of 12 test car drivers and a variety of test crash scenarios. The SIM tool was then calibrated and configured to estimate safety benefits in terms of reduced numbers of crashes, vehicles involved, and fatalities if A-CMBS were installed on all light vehicles in the United States.


Models developed from test track studies, driver simulator experiments, and crash database archives indicated that with total market penetration, the A-CMBS would reduce crashes by 511,336 per year and decrease fatalities by 1,623 per year.

The data below derived from the source report (Table 84, Table 85 and Table 2a) summarize the system impacts at the US 2005 calendar year level.

Crash problem size for entire US motor vehicle fleet
Overall effectiveness on entire US motor vehicle fleet [1]
Estimated benefit for vehicle occupants [2]
Estimated benefit for pedestrians [2]
Total estimated benefit [2]
Estimated Number of Crashes
Estimated Number of Vehicles
Estimated Number of Fatalities

[1] Overall effectiveness = effectiveness in reducing Technology Relevant Crash Type (TRCT) crashes multiplied by the ratio of the number of relevant baseline crashes for each TRCT to the total number of baseline crashes for each TRCT.

[2] A-CMBS benefit estimates are equal to the baseline crash problem size multiplied by the overall effectiveness estimates.

Advanced Crash Avoidance Technologies (ACAT) Program – Final Report of the Honda-DRI Team, Volume I: Executive Summary and Technical Report

Advanced Crash Avoidance Technologies (ACAT) Program – Final Report of the Honda-DRI Team, Volume I: Executive Summary and Technical Report
Publication Sort Date
Van Auken, R.M., et al.
U.S. DOT National Highway Traffic Safety Administration (NHTSA)
Other Reference Number
DOT HS 811 454

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