WASHINGTON, D.C. – The National Highway Traffic Safety Administration has passed a strict new braking rule for heavy trucks designed to significantly reduce fatalities, injuries and property damage by reducing their stopping distances by 30 percent.

The July Final Rule was the conclusion of a rulemaking that began in December 2005, after the agency published An Analysis of Fatal Large Truck Crashes. The report painted a sobering statistical picture. According to 2006 data, large truck fatal crashes comprised 12 percent of all highway fatalities in that year. A total of 385,000 large trucks were involved in crashes –  with 4,732 resulting in 4,995 fatalities; 106,000 people were injured in crashes with large trucks. Three-quarters of the killed and injured people were occupants of another vehicle. These statistics were buttressed by a 2005 Federal Motor Carrier Safety Administration analysis, which found that the fatality rate for large truck crashes was 66 percent higher than that of passenger car crashes. Combination trucks – tractor-trailer combinations – alone had a fatality rate nearly double that of passenger vehicles. The crash fatality rate for single-unit trucks was about 23 percent higher than for passenger vehicles.

Under current Federal Motor Vehicle Safety Standard 121, most truck tractors are required to stop within 355 feet, when tested at 60 mph, pulling an unbraked control trailer, loaded to their Gross Vehicle Weight Rating; and within 335 feet, when tested at 60 mph in the unloaded condition. The emergency brake stopping distance is set by 720 feet, when tested at 60 mph in the unloaded condition. The standard doesn’t specify different requirements for different vehicles based on their weight or number of axles.

The new rule – covering 130,000 tractor trailers manufactured annually – will require heavy tractor trailers to stop in not more than 250 feet when fully loaded at a speed of 60 miles per hour, and 235 feet when at their lightly loaded weight. A small number of very heavy, severe service, tractors will be required to stop within 310 feet. This amounts to a 30-percent reduction in the stopping distance compared to the current standard, and well above what the trucking industry argued for. Truck manufacturing groups maintained that the reduction should be limited to 20-25 percent, citing increased costs and the complexity of the upgrade – especially for two-axle and severe service tractors.

But the agency decided that the benefits of a 30 percent reduction far outstripped those of a more limited rule. The regulatory analysis estimated twice as many benefits in fatalities and serious injuries at the 30-percent reduction versus 20 percent; and a five times more significant savings in property damage estimates.

“The purpose of these amendments is to reduce the number of fatalities and injuries associated with crashes involving tractor-trailer combinations and other vehicles,” the agency said. “Once all subject heavy truck tractors on the road are equipped with enhanced braking systems, we estimate that annually, approximately 227 lives will be saved and 300 serious injuries will be prevented. In addition, this final rule is expected to prevent over $169 million in property damage annually, an amount which alone is expected to exceed the total cost of the rule.”

The agency also said that its testing had demonstrated that there were several readily available solutions to meet the new requirements. They included the installation of enhanced drum brakes, air disc brakes, or hybrid disc/drum systems, which many vehicles in the commercial fleet already use.

NHTSA had originally proposed reducing emergency brake stopping distances by 20-30 percent but decided to drop it after the Truck Manufacturers Association stated that manufacturers would have to modify the ABS algorithms to allow more drive wheel lockup, compromising vehicle stability and control.

“NHTSA considered this, as well as the relative rarity of a crash-imminent situation during a brake failure, and decided to maintain the status quo,” the agency said.

The agency gave manufacturers two years lead time for the majority of three-axle tractors to comply with the Final Rule, and four years for two-axle and severe service tractors.