Dec. 28, 2000
Electronically controlled antilock brakes (ABS) are about to stage a comeback in big trucks and trailers.
Electronically controlled antilock brakes (ABS) are about to stage a comeback in big trucks and trailers. Federal safety regulators, who are requiring installation of the systems, believe recently developed hardware to be sound. Four potential producers, each with a connection in Europe, are confident they have the right devices for what promises to be a multi-billion-dollar market.

Potential ABS users fall into three groups: those who have tried antilocks and like them; others who had service problems with the systems they tried; and a majority who have been unwilling to buy the devices even at discounted prices.

There are technical questions about how to link antilocks in tractors with those in trailers. With an answer to this problem needed in less than two years, researchers are rushing to find a solution.

Another fly in the ointment is the insurance industry's comment that antilocks are not delivering the benefits expected of them. ABS suppliers blame much of this problem on vehicle operators who have not taken the time to learn how to use the devices properly.

Any discussion of ABS today has to start with a bit of history. It is well known that vehicle skidding occurs when brakes lock up the wheels. Skilled drivers worked around skidding perils by "pumping" the brakes-releasing them just as they started to lock-up.

For years, "antiskid" braking-very fast brake pumping managed with advanced electronic controls-was used to bring aircraft to a stop. Antilock systems for trucks made their first splash on an automotive test track in the late '60s.

Soon, federal regulators required the use of antilocks on air-braked trucks and trailers. However, these early systems had a wide range of failures. Sometimes brakes didn't work when applied. At other times, they went on with no one touching the brake pedal. There also were times when use of a two-way radio in the truck cab applied the brakes.

Lack of time for development and adequate testing got much of the blame. It became apparent that the electronic controls being used at the time were not up to their assignment and researchers didn't have a grip on their shortcomings.

A series of protests in Congress and a number of court cases, put antilock brakes on the back burner for two decades. Lawmakers finally told safety regulators not to bring antilocks back until they solved the problems and the brakes were found to be sound. Today the National Highway Traffic Safety Administration (NHTSA) believes they have cleared the hurdles.

A 1995 NHTSA decision requires antilock systems to be installed on all new air-braked tractors by March 1, 1997, and on air-braked trailers and straight trucks a year later. Trucks with hydraulic brakes must be in compliance by March 1, 1999. The rule applies to all units over 10,000 lb gross vehicle weight.

Companies poised for the ABS comeback are the Bendix air-brake business, now a unit of AlliedSignal's turbocharging and truck brake systems operation, which is cooperating with the Knorr brake factory in Germany; a recently formed joint venture between Eaton and Bosch, which have brake interests in Germany and America; Midland-Grau, part of the Echlin American-German conglomerate whose components include the Berg and Wagner lines, which were in the antilock business when the systems were required in 1975 ; and Rockwell WABCO. This U.S.-German joint venture began in 1990; however, both companies offered antilocks in 1975.

All producers have developed new-generation antilock systems that passed NHTSA testing. Improvement in electronic components got credit for many advances in systems "that deliver safe panic stops within traffic lanes." Recent developments have put the finishing touches on the new generation of antilocks.

A good number of recently introduced antilock systems have been economy models with fewer controls or valves than the deluxe models shown earlier.
When announcing the effective dates of the antilock requirements, NHTSA estimated a system for an air-braked tractor would cost just over $850, while a system for an air-braked straight truck would cost a little less than $700.

However, the industry does not know just how much money truck operators will pay for antilock systems. They have been offered as standard equipment-possibly at reduced introductory prices-for some time. Large groups of buyers have shunned the antilock in favor of taking the price break of a "delete option." Once they are required, there will be no delete options.

Sensitive to remarks about drivers and mechanics not being prepared to properly operate and service new antilock systems, Midland-Grau has clearly been on an all-out publishing program through the early months of this year. Modal Power TK2 is the name of the firm's latest antilock system. It is already backed-up with a thick, illustrated installation and service manual.

Since 1975, most antilock attention has been focused on air-brake systems. Will hydraulic brake systems be neglected when antilocks are required in 1999?

"No way," said Leonard C. Buckman, president of Rockwell WABCO. "WABCO has been deeply involved with hydraulic antilocks in Europe even if those systems have not received great attention here."

Antilocks of all types received much attention in Europe as they sat on the regulatory back burner here after the mid-70s. This explains why American antilock suppliers have had European partners while the U.S. government was deciding what to do about antilocks.

Kelley is a truck writer based in Dearborn, Mich. You may write him in care of the editor.

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