The federal government last week proposed a new motor vehicle safety standard to require electronic stability control (ESC) systems on large commercial trucks, motorcoaches and some other large buses — but not school buses.

ESC systems have sensors that monitor vehicle movement and steering. They can help mitigate rollover incidents by using automatic computer-controlled braking, and they can aid the driver in addressing severe understeer or oversteer conditions that can lead to loss of control.

The National Highway Traffic Safety Administration (NHTSA) estimates that a standard requiring ESC on large trucks and large buses would prevent up to 2,329 crashes, eliminate an estimated 649 to 858 injuries, and prevent between 49 and 60 fatalities per year.

“We’ve already seen how effective stability control can be at reducing rollovers in passenger vehicles — the ability for this type of technology to save lives is one reason it is required on cars and light-duty trucks beginning with model year 2012,” NHTSA Administrator David Strickland said. “Now, we’re expanding our efforts to require stability enhancing technology on the many large trucks, motorcoaches and other large buses on our roadways.”

Along with school buses, transit buses are excluded from NHTSA’s proposed rule, which explains that in fatal crash data that were analyzed, “most of the transit bus and school bus crashes are not rollover or loss-of-control crashes that ESC systems are capable of preventing.”

However, the agency said that it “seek[s] comment on whether this proposal should be applied to the types of buses that are excluded from the proposed rule, such as school buses and transit buses.”

Mike Martin, executive director of the National Association for Pupil Transportation (NAPT), told SBF that although the NHTSA proposal leaves out school buses, the National Transportation Safety Board (NTSB) “clearly wants stability control systems on all heavy vehicles” and has issued recent recommendations on that subject.

The discrepancy between the two key safety agencies is a cause for concern for the pupil transportation community, according to Martin.

“Anytime we get one of them that says one thing and another that says almost the exact opposite, it leaves you in a bit of a quandary on what to do from a policy standpoint,” he said.

Martin noted that NAPT President Alex Robinson and her counterparts at the other national industry associations, the National Association of State Directors of Pupil Transportation Services and the National School Transportation Association, have had conversations about working together more. The ESC proposal could be a good focus for collaboration.

“This rulemaking seems like a perfect opportunity for us to join forces and analyze the differences in perspective at NHTSA and NTSB and then work together to reconcile the differences,” Martin said.

To view NHTSA's full proposal, go here.