Staying Right-Side-Up

How one fleet is keeping its trucks on the road and out of the shop with stability control

Mark Hadley is a believer. When Hadley, director of maintenance for West Valley City, UT-based Central Refrigerated Service, Inc., spent a few minutes behind the wheel of a tractor equipped with Bendix Commercial Vehicle Systems' ESP Electronic Stability Program back in 2006, he knew immediately that he had to spec' all his new tractors with the innovative safety technology.

When Hadley received the invitation to Houghton, MI to attend a Bendix "Ride 'n' Drive" ESP demo, his response was an immediate "Heck, yea!" He was already interested in a rollover-prevention systems for his fleet, but the Bendix package intrigued him because it represented a full stability control system.

"I was extremely impressed, not only by the roll stability, but particularly when they went around the oval track," Hadley recalls. "They went around an oval track at 40 or 45 miles per hour, on ice. I could make the turns and everything just fine, but as soon as they flipped the system off, I was completely out of control. I had to slow down to about 20 miles per hour before I could even think about getting this vehicle back under control"

Hadley went back home to Utah with his mind made up: "I told Volvo that we would be the first ones on the bandwagon," he recalls. "In fact, I asked when it would be available and they said second quarter. Well, we already had our build of trucks going, and we insisted that we get that on as soon as it was available.

"You always think, 'never get the first of anything,' because you're going to get to deal with all the flaws," Hadley says. "Well, this thing was flawless right out of the gate, and it's been that way ever since."


There's a big difference between roll only stability systems, sometimes called RSP or RSC, and full stability systems like ESP, according to Fred Andersky, marketing director, electronics, for Bendix Commercial Vehicle Systems. "The difference is that there are some additional sensors in a full stability system that measure both what the driver wants the vehicle to do, and what the vehicle is actually doing from a directional standpoint," he says.

"Obviously, we're using the wheel speed sensors from the ABS to provide information," Andersky continues. "But, we're also then using a lateral acceleration sensor that measures the side-to-side forces that would occur in a traditional rollover, and a yaw sensor, or directional stability sensor, that measures where the truck's going, and a steer angle sensor, in which the steering column goes through the sensor, so we can measure the driver's input."

That expanded sensor system is supported by additional braking capability: a roll only system will brake the drive and trailer axles, but a full stability system will selectively brake the drive, trailer and steer axles. "What that allows the system to do is not only help slow the vehicle down quickly, but also redirect the vehicle as necessary to get on the path on which the driver wants the vehicle to go," he says.

All of which meshed perfectly with Central Refrigerated's focus on safety. "We've had our little issues--brake valves and so forth--but as a whole, it's been a no-brainer," says Hadley. "So much so that Volvo went and put it on as a standard item in '07. The reliability was there right out of the gate, and we hit the ground running with it."


Many fleets would need a very clear and strong ROI calculation before investing in sophisticated safety technology for 1,850 tractors, but for Central Refrigerated, "payback" was not a driving factor in the decision to spec' ESP on its tractors. According to Hadley, the company's CEO believes that safety is its own reward, and so an investment like this is simply the right thing to do.

"Our CEO is all about safety," Hadley says. "He wants the best safety record in the country, for the health of our society and our drivers."

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