By Paul Abelson
According to the Federal Motor Carrier Safety Administration's 2007 “Unit Costs of Medium/Heavy Truck Crashes,” the average crash costs more than $90,000.
If someone's injured, costs approached $200,000; a fatality raised the figure to more than $3.6 million. Six years later, we can add inflation and increasingly generous jury awards to these figures.
That's why crash avoidance systems, early warning devices, and stability control are as important as insurance. But because they (sometimes) increase vehicle price, many public fleets haven't bought or even begun evaluating these features. “We'd love to test them, but we can't even get the replacement trucks we need right now,” says Bruce Nelson, assistant fleet superintendant, City of Madison, Wis.
Although budgets are tight, self-insured operations should keep in mind the systems pay for themselves when they avoid just one incident.
One technology, roll stability control, safeguards top-heavy vehicles that are subjected to rollover-inducing conditions.; and can be very effective on dump trucks, salt spreaders, boom trucks, and concrete mixers.
A couple of years ago, I participated in a demonstration of Bendix Commercial Vehicle Systems' new electronic safety equipment, including electronic stability control, which incorporates roll stability control. Several trucks were equipped with special outrigger wheels, and a driving course was marked to simulate an abrupt lane change and a fast decreasing radius turn.
The lane change called for left turns followed immediately by a correcting right turn. It was done at only 20 mph to simulate a car stopping suddenly in front of the truck.
With the electronics turned off, the truck initially swayed right, then rolled left after the correction. I didn't overturn, but only because the “training wheels” did their job.
On the second pass, the roll stability control system was on. The truck swayed, but the outriggers never touched ground. I can also attest to the skid-reducing properties of the systems on snow and ice. At the company's winter proving grounds in Houghton, Mich., they simulated a car that slid through a stop sign. I was able to steer several trucks around it without losing control.
The power of computers
The safety afforded by Bendix, Eaton, Meritor WABCO , and Haldex is systems is due to developments in high-speed computers, which enable stability control and its variant, roll control. These systems are standard equipment on many new trucks.
Anti-lock braking systems (ABS) are the base technology. ABS measures wheel speed. If one slows or stops more than others, pressure is reduced to its brake. That ability to control each brake independently does more than just prevent brake lock. Stability systems can apply brakes selectively. With steering and lateral acceleration sensors, computers can determine if a skid is starting.
Add roll sensors, and the high-speed processors can reduce engine power and apply brakes to halt a skid almost before it starts. Often, the correction's made without the driver realizing anything happened.
Computers also help avoid crashes. The Mobileye system, Bendix' VO-RAD, and the Eagle Eye Obstacle Detection System by Transportation Safety Technologies all alert drivers of dangers ahead.
Mobileye uses image processing to monitor lane positioning. It warns of lane departures except when turn signals are on. Mobileye can be coupled with forward-looking radar for headway monitoring and warning (HMW), an adaptive cruise-control system that adjusts vehicle speed to maintain a following interval in traffic.
Vehicle on-board radar (VORAD) uses radar to search the road for potential threats. Some models feature adaptive cruise control that de-fuels the engine and, in extreme cases, applies the Jake Brake. In Mercedes Benz automobiles it stops the car. Only driver acceptance has kept this feature from being adopted for trucks.
Near obstacle detection alerts drivers to objects in blind spots and behind the vehicle. Side alerts are activated when directional signals turn on, although many systems use lights alone to constantly monitor blind spots. Backup alerts are active with the truck in reverse.
Setting future safety standards
Autonomous crash avoidance and mitigation technologies are also under development.
By combining radar input and GPS systems, vehicles can use short-range radio to tell other vehicles where they are, where they're going, and when they'll be at any given point on their route. Each vehicle's computer can warn its driver of potential collisions. If the driver doesn't respond appropriately, the systems slow the vehicle, apply the brakes, and, when equipped with electric steering, change the vehicle's course.
With proximity warnings from radar giving 360° coverage of blind spots, a vehicle can also accelerate to avoid rear-end crashes.
These systems will add minimal cost to vehicles because most of the technologies are already in place.
— Paul Abelson ([email protected]) is a former director of the Technology and Maintenance Council (TMC) of the American Trucking Associations, a board member of Truck Writers of North America, and active in the Society of Automotive Engineers.
