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Prevent Collisions by Using Enhanced Vehicle Safety Technology

• Reduce rear-end collisions through use of adaptive cruise control and collision avoidance system technologies.

The Safety Board believes that developing and installing new technologies—such as adaptive cruise control and collision warning systems—in commercial trucks, buses, and passenger vehicles will substantially reduce accidents.  This assessment comes from numerous Safety Board investigations.  In a 2-year period, for example, the Board investigated 9 rear-end collisions in which 20 people died and 181 were injured.  Three of the accidents involved buses and one accident involved 24 vehicles.  Common to all nine accidents was the rear-following vehicle driver’s degraded perception of traffic conditions ahead before striking other vehicles.  These accidents did not involve the use of drugs, alcohol, or vehicle mechanical defects.  The investigation showed that sun glare, fog, smoke, fatigue, distractions, and work zones interfered with a driver’s ability to detect slow-moving or stopped traffic ahead and resulted in rear-end collisions.  According to the U.S. Department of Transportation, preliminary analyses have shown that 1,836,000 police-reported crashes, or about 48 percent of accidents, could be prevented by rear-end or run-off-the-road and lane change collision warning systems (CWS).(1)

Summary of Action
As of 2001, the Department of Transportation had established an Intelligent Vehicle Initiative (IVI)—the goal of which was to improve significantly the safety and efficiency of motor vehicle operations by reducing the probability of motor vehicle crashes—as a major component of the Intelligent Transportation System (ITS) program.  As part of the IVI, NHTSA evaluated the performance of CWS and adaptive cruise control (ACC) by participating in field operational tests of vehicles equipped with advanced safety systems.  In May 2005, NHTSA released the results of its passenger vehicle testing, Automotive Collision Avoidance System Field Operational Test Final Program Report, showing potential to reduce rear-end crashes by 10 percent and reporting positive user reaction to the systems.  The final report on the commercial vehicle field testing conducted for the U.S. Department of Transportation by Battelle and Volvo Trucks North America, Inc., was released in January 2007.  The preliminary findings of the report indicate that a combined CWS and ACC bundled safety system account for a statistically significant reduction in rear-end crashes through reduced exposure to safety-critical driving scenarios.  The Board has requested but has not yet received any information on NHTSA’s interpretation of the commercial vehicle testing or timeline for future actions to mandate use of this technology.

NHTSA, along with its cooperative partners—the FHWA, the FMCSA, and RITA—appears to be working consistently, although slowly, on this important technological safety issue.  The preliminary results of the testing on advanced safety systems are encouraging, but rulemaking is needed to ensure uniformity of system performance standards, such as obstacle detection, timing of alerts, and human factors guidelines, on new passenger and commercial vehicles.

Action Remaining
Continue efforts to develop performance standards for enhanced vehicle safety technology in new passenger and commercial vehicles.

Safety Recommendations

H-01-6 (NHTSA)
Issued May 25, 2001
Added to the Most Wanted List: 2007
Status:  Open—Acceptable Response
Complete rulemaking on adaptive cruise control and collision warning system performance standards for new commercial vehicles. At a minimum, these standards should address obstacle detection, timing of alerts, and human factors guidelines, such as the mode and type of warning.  (Source: A 2001 special investigation on technology to prevention rear-end collisions [NTSB/SIR-01/01])

H-01-8 (NHTSA)
Issued May 25, 2001
Added to the Most Wanted List: 2007
Status:  Open—Acceptable Response
Complete rulemaking on adaptive cruise control and collision warning system performance standards for new passenger vehicles. At a minimum, these standards should address obstacle detection, timing of alerts, and human factors guidelines, such as the mode and type of warning.  (Source: A 2001 special investigation on technology to prevention rear-end collisions [NTSB/SIR-01/01])

November 2007

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