Heavy Duty: Vehicle Stability Systems

Stability and rollover systems: Can your fleet afford NOT to have these?

Kansas City, MO-based Haldex Commercial Vehicle Systems offers a Trailer Rollover Stability System for heavy-duty trucks. Haldex Brake Systems product manager Duane Stocksdale says having a system on a trailer is more important than on the tractor.

“If you’re going to get the best performance, you’re probably going to put it on both, (but) we believe the roll event begins at the trailer and if you look at videos of a vehicle going into a roll event, you always see the back wheels on the trailer start to lift off before you ever see anything in the tractor,” Stocksdale says. “We’ve had several demos and people sitting in the tractor are just amazed when they look in the mirror and actually see the trailer pivoting up on the outriggers and they aren’t feeling a thing in the tractor itself.” He says the system received a new tweak in January, providing added safety features.

“When you go into a roll event and the system automatically applies the brakes without driver intervention, (it) applies the brake lights so a vehicle behind the trailer can see there is a stopping event happening,” Stocksdale says.

The key to preventing rollovers is simple—reduce speed rapidly, Stocksdale says.

“Once you start to approach that roll threshold, you’ve got to get that vehicle slowed down and apply the brakes as quickly as you can and help him avoid that,” Stocksdale says.


Husted said he has not heard of a single maintenance issue with the systems on Garner Trucking’s 25 Columbias, which have remained accident-free since the install. He says the training benefits became immediately apparent, though, thanks to the information the units store for download during preventative maintenance.

“It will tell us every time the system has been activated (and) gives you two points,” Husted says. “One, the unit was approaching the point where the system needed to be activated and (two) how many times the systems had to physically intervene. And obviously if we have reading where it had to intervene, we bring the driver in and have a talk with him.”

Being able to sit down with a driver with data “in hand” has proven to be a very proactive and effective way to reinforce safety.

“There are times where the driver is actually unaware that anything had occurred,” Husted says. “Even though the vehicle decelerated, they have a tendency to believe they got the unit back under control themselves. Where when we see that the system intervened, we show him, ‘Look, this happened, do you recall this?’ I have never had a driver come in to me and admit to knowing the system saved his butt—I think that’s just human nature—but now they are aware we have seen this, we are monitoring this and they need to be more cautious.”

According to FMSCA, fleet safety managers point to inadequate training and experience as one of four basic factors that cause rollovers, along with excessive speed, driver inattention, driver fatigue. Korn says since many fleets want to know how their vehicles are being driven, the information these systems can provide is critical.

“A lot of fleets have found that to be very effective, because this increases the safety margin,” Korn says.” The best situation would be if they never intervene, because that way the vehicle is being driven very conservatively.”


As one fleet boss at a recent SAE technical session on stability control systems put it, “If you can get ‘em, get ‘em.” There is a growing variety of systems out there, and the vast majority opinion of industry professional is they provide fleets a good, fairly quick return in investment and serve as good training tool to boot. If you are one of the fleets still sitting on the sideline because you can’t afford them or have a spotless safety record, a startling revelation may just be waiting around the next corner.


If your techs are adept at handling ABS and electrical issues, learning to install, troubleshoot and maintain roll stability systems should be an easy transition. For instance, Haldex Brake Systems product manager Duane Stocksdale says there are only two differences between the Haldex system and a typical ABS.

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