The National Highway Traffic Safety Administration (NHTSA) has finally issued long-awaited new braking standards for commercial truck tractors, mandating that a tractor-trailer traveling at 60 miles per hour must come to a complete stop in 250 feet, versus the old standard of 355 feet – a reduction of truck stopping distance of roughly 30%.

For a small number of very heavy severe service tractors, the stopping distance requirement will be 310 feet under these same conditions. In addition, this final rule requires that all heavy truck tractors must stop within 235 feet when loaded to their “lightly loaded vehicle weight” (LLVW).

Though this new regulation is going to be phased in over four years beginning with 2012 models, NHTSA said three-axle tractors with a gross vehicle weight rating (GVWR) of 59,600 pounds or less must meet the reduced stopping distance requirements specified in this final rule by August 1, 2011.

Two-axle tractors and tractors with a GVWR above 59,600 pounds must meet the reduced stopping distance requirements specified in this final rule by August 1, 2013, the agency noted, adding that voluntary early compliance is permitted before those dates.

NHTSA also stressed that this new rule applies only to truck tractors and does not impact single-unit trucks, trailers and buses.

“This is a very tough rule, but we believe the technology is out there to help trucks comply with it,” said Eric Bolton, a NHTSA spokesman. “We’re a scientific agency, so a significant amount of research went into developing this rule. We’ve made sure from a technology perspective that we’ve dotted all the i’s and crossed all the t’s.”

The agency estimates that the new braking requirement will save 227 lives and prevent 300 serious injuries annually, while reducing property damage costs by over $169 million on a yearly basis – an amount which alone is expected to exceed the total cost of the rule, NHTSA pointed out.