Working With a Net

by Steve Macleod

Putting a trucker behind the wheel of the highest quality equipment can greatly reduce the chances of a collision.

When those parts are outfitted with computer components that can make Rain Man-esque calculations, the chances of a collision are reduced even further.

Considering all the costs associated with a collision — and they can jump even higher if you’re Stateside and caught up in litigation — an ounce of prevention is worth more than a pound of cure.

A handful of manufacturers with safety on the brain have developed a few different devices that can be hardwired into the truck as preventative safety measures, but sit idle until actually needed. Without actually affecting how a truck drives in normal situations, these devices will prevent rollovers, rear-end collisions and sideswipes.

While they are just options now for spec’ing out a new truck, the U.S. government is taking a serious look at making them mandatory.

STUDY SESSION

Last fall, the National Highway Traffic Safety Administration (NHTSA) published a report called "Safety Benefits of Stability Control Systems For Tractor-Semitrailers." The study analyzed both roll-stability control (RSC) and electronic stability control (ESC), which adds understeer/oversteer sensing, and they’re both proven to be huge difference makers.

This study might just be the final effort in moving towards a rule calling for stability control systems to be mandated in heavy trucks.

NHTSA’s study was conducted by the University of Michigan Transportation Research Institute (UMTRI) under a co-operative agreement between NHTSA and Meritor WABCO Vehicle Control Systems. NHTSA supplied the money as a grant to Meritor WABCO, which then supplied expertise to make the simulator test hardware work and linked all the equipment manufacturers, while funding UMTRI to do the testing and analysis.

Although the study wasn’t conducted in a real-world situation, the estimates from the study suggest RSC could prevent at least 3,489 rollover crashes in the U.S. annually and as many as 4,659 with ESC.

Matt Williams, manager of fleet sales, training and customer service with Meritor Wabco, figures a NHTSA mandate for roll stability will happen this fall and then OEMs will have about two years to comply.

KEEP ON ROLLING

In late June, nearly 100 people gather on the tarmac at the Red Deer Regional Airport in Alberta.

A silver-colored semi with a tanker in tow barrels down the asphalt strip towards the crowd before the driver cranks the wheel. The tanker would’ve rolled if not for the training wheel stretching out from its side. 

What has four wheels and flies? And erratic
car, that’s what. When it comes to
avoiding a collision, every second counts.

On the next trip down the strip, the tractor-trailer’s outrigger doesn’t come close to touching down, despite the driver having the accelerator matted.

Meritor Wabco’s SmartTrac stability control system is engaged to make sure the tires on the truck and trailer stay on the pavement.

With the advancements in truck suspensions and air-ride seats, it’s becoming more difficult for truckers to feel when a truck is on the verge of rolling over. From inside the cab, it’s not even noticeable that the Meritor test truck was on its outrigger just a second earlier and the spinning training wheel in the side mirror is the only clue.

"The key to stability is we can identify a problem long before a driver can," explains Williams.

"We’ve developed a pyramid of safety, built off ABS brakes," he notes. "By adding components to fit the system, we can build stability control by building off of ABS brakes."

The system uses engine torque output to identify a truck’s centre of gravity. If it senses that the truck will become unstable, the RSC system will decrease engine torque, activate the engine retarder, and apply the tractor and trailer brakes, in that order.

ESC does the same and adds yaw sensing and thus the added capability of seeing and then controlling vehicle understeer and oversteer, which are directly related to loss of control.

These stability systems are designed to operate as a last resort to prevent a rollover and aren’t meant to replace good driving habits. Even when applying the brakes, it’s important for the driver to steer and regain control of the truck.

"The system will never override a driver’s input," explains Williams. "If they become re-engaged, then they’re back in control."

Meritor’s system is available on the Daimler family of trucks and Navistar’s models. Bendix has developed similar roll stability technology that is offered by a number of other truck makers.

Both manufacturers offer stability systems designed for trailers as well.

KEEPING SOME DISTANCE

Another Meritor Wabco safety system on display at the Red Deer Regional Airport was the OnGuard system. The device uses forward-looking radar sensor technology featuring advanced algorithms to monitor the distance of the vehicle ahead.

Riding shotgun in the cab of a test truck, a passenger vehicle speeds by on the tarmac, cuts in front and slows down. The driver keeps the accelerator on the floor and ignores the audible and visual warnings of the in-cab dash display.

Since the driver failed to take appropriate corrective action, the system quickly de-throttles and brakes, bringing the rig to a halt a few feet from the passenger vehicle.

A radar in the truck’s bumper detects objects in front of the rig and maintains a 3.6-second following distance. The OnGuard system is always on, and becomes active once the truck eclipses 15 mph.

The sensor has a scope of 10.5 degrees horizontally and 3.5 degrees vertically, so it’s not big enough that it will react to debris like roadkill, but it’s enough that it will detect people or small cars. OnGuard also has an internal gyro to detect an approaching curve and adjusts the radar beam as necessary to see objects around the bend.

"At 60 mph a truck travels 88 feet per second," explains Williams. "It’s estimated 90 percent of collisions can be avoided with just one more second of time for the driver. That’s what we try and do is give them one more second.

"We give the driver every effort to get engaged and only take over at the last second. If the driver gets re-engaged he’s back in control and it won’t override the driver."

There have been more than 6,000 units put in the field since 2004 and in two-thirds of the trucks an OnGuard event was recorded.

In a comparison of 390 trucks with the system and 390 trucks without the system — 25 million total miles — the trucks with the system had a 58.9-percent reduction in preventable DOT reportable accidents, a 32.1-percent reduction in total DOT accidents, and a 32.4-percent reduction in total accidents.

Once again, Bendix is also involved with similar technology through the company’s Adaptive Cruise Control (ACC). The system lets the vehicle maintain a set following interval, based on time, between the truck and the lead vehicle, helping to avoid collisions if the driver is momentarily distracted or if the lead vehicle suddenly slows.

The system also uses throttle reduction, engine retarder, and brake application to help decelerate the vehicle and maintain the intended following distance. It also provides audio and visual warnings as the truck closes in on the lead vehicle.

Similarly, Eaton’s VORAD Collision Warning System helps drivers take evasive action before accidents happen. VORAD (Vehicle On-board radar) helps keep drivers aware of safe following intervals and warns of potential hazards ahead, such as a stopped or slow-moving vehicle.

CASHING IN

According to the NHTSA roll stability study, ESC savings from rollovers and LOC crashes are estimated at US$1.738 billion annually. For RSC, the savings are estimated at US$1.456 billion a year.

Depending on how much money your fleet has spent cleaning up collisions, Meritor Wabco puts the ROI of a stability system between $1.66 and $9.36 for each dollar spent. For the OnGuard Collision Warning System ROI is between $1.33 and $7.22.

So, if you’re scouting the market for a new truck take a closer look at what safety options will come standard with the truck and what options need to be added on; and if you’re happy with your current set of wheels, aftermarket options are available and a pretty stable choice.

Either way, keeping your wheels on the pavement will translate into more time hauling freight, and a little help could go a long way.  

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