Stability systems help keep the shiny side up

by James Menzies

WATERLOO, Ont. – In light of a rash of high-profile truck rollovers in the Greater Toronto Area (GTA) this summer, Volvo Trucks and Bendix held a three-day demonstration of their electronic stability system here in late October.

Customers, media and law enforcement officers were on-hand to see how electronic stability systems such as Volvo Enhanced Stability Technology (VEST) can help reduce the risk of truck rollovers. Volvo’s system, engineered by Bendix and now standard on all Class 8 Volvo trucks, detects when a rollover is imminent and then intervenes by decelerating the truck and applying the brakes to individual axles as required. Fred Andersky, marketing manager of electronics with Bendix, explained the system can detect potential rollover conditions before the driver does, allowing the system to take action to prevent it from occurring. The system is equally effective whether activated during an avoidance maneuver (such as in an intersection) or a J-curve (such as a highway on- or off-ramp), Andersky explained.

To back up this claim, Volvo and Bendix had two trucks equipped with the VEST system on-hand for demonstrations Oct. 29-31. One was pulling a tanker trailer loaded to 80,000 lbs. Several compartments were only partially filled with water, to maximize the sloshing effect of a liquid load. The other truck pulled a flatdeck A-train loaded to 75,000 lbs.

I rode in the VT-880 with A-train in tow along with Bendix senior staff engineer Charlie Ross. Admittedly, this wasn’t the first time I’ve participated in this demo and it wasn’t my first time riding along with Ross. Ross scared the bejesus out of me during a Bendix demo in Houghton, Michigan last winter. This time around was less stressful, as I was now fully convinced the system worked as advertised.

The stability system boasts a level of electronic sophistication that cannot be matched by any human. It can detect when a rollover is imminent by reading data from wheel speed, yaw rate, lateral acceleration and steering angle sensors. When critical threshold levels are approached, the system will intervene to assist the driver in getting the vehicle back under control.

The VEST system can override the throttle and apply the brakes to each axle as required, slowing the vehicle and allowing the driver to regain control.

Andersky explained the Volvo/Bendix system is more advanced than other stability systems that offer “roll-only” protection. He pointed out roll-stability systems lack the steer angle and yaw sensors, which allow VEST to compare a driver’s inputs to a vehicle’s own actions.

“Full-stability systems offer more sensors providing more information and a quicker reaction time,” Andersky explained.

He showed several videos comparing the two types of anti-rollover systems. The trucks in the videos were equipped with outriggers (think training wheels for trucks) to save them from the destruction that ensues when a tractor-trailer ends up shiny side down.

“When the outrigger hits the pavement, that indicates a rollover,” Andersky explained.

In one video clip, a truck equipped with a roll-only system showed the potential to roll over at 35 mph while the same truck equipped with the VEST system could make the same maneuver at 50 mph before the outriggers touched the ground. That 15 mph difference provides a driver with more room for error, Andersky pointed out.

While the system is now standard on Volvo trucks, it remains an option on most other truck brands. Andersky said many customers dismiss electronic stability systems because of the cost associated with them and the fact they mistakenly believe ABS is designed to perform the same tricks.

“ABS works great, but the driver has to apply the brakes first,” he pointed out. In many cases, as proven by further video shown at the event, it’s too late to save the truck by the time the driver applies the brakes.

Also, VEST is designed to work in all conditions, including rain snow and ice where even ABS may be limited. Ross has conducted countless versions of the VEST demonstration and he told me he has yet to see a single driver climb from the truck unconvinced of the system’s effectiveness. Still, Andersky said it does have its limitations.

“It’s not a replacement for a good driver,” he pointed out. Take a 15 mph corner at 50 mph, for instance, and no technology in the world is going to save you. But “If a driver is going just a little too fast, this system can really help them.”


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