OEMs Object to Test Plan For Stability Control Rule

This story appears in the July 30 print edition of Transport Topics.

WASHINGTON — While expressing support for a proposed electronic stability control mandate for heavy vehicles, the companies that make those vehicles strongly objected to the regulation’s test procedure for getting vehicles certified and urged federal regulators to consider alternative tests.

Representatives of truck makers said one of the tests the National Highway Traffic Safety Administration would require to demonstrate ESC effectiveness is expensive and does not replicate real-world situations, among other problems.

“Sine-with-dwell is a complex and burdensome test procedure developed for passenger vehicles,” Tim Blubaugh, executive vice president of the Truck and Engine Manufacturers Association, said at a July 24 hearing on the proposal at NHTSA’s headquarters. “It does not work for heavy-duty tractors.”

NHTSA proposed in May to require that all new heavy vehicles be equipped with ESC, which is designed to prevent rollover and loss-of-control crashes by throttling down the engine or applying brakes in dangerous situations (5-21, p. 1).

But Blubaugh and speakers from some of the country’s biggest truck makers urged NHTSA not to require that they test each model of truck using sine-with-dwell.

The maneuver requires that the vehicle be quickly steered in one direction, then quickly steered in the other direction and kept in that steer position, all at a high speed. If the ESC system works as intended, the vehicle neither rolls over nor spins out of control.

Though sine-and-dwell is required to test light-vehicle ESC, it is impractical for heavy vehicles, Blubaugh said, adding that ESC’s effectiveness has been proven through other tests.

“The sine-with-dwell test maneuver requires installing expensive and complicated equipment on the vehicles and conducting complex post-processing of the test data,” he said. “Further, the nature of the performance maneuver has the potential to damage the vehicle tested.”

Truck makers usually sell the trucks they use for tests, Blubaugh said. But if sine-with-dwell damages the truck, its manufacturer wouldn’t be able to sell it.

Furthermore, TEMA believes only one testing facility in the United States has the proper space and equipment to perform a sine-with-dwell on a heavy truck, Blubaugh said.

Also, a truck’s tires and trailer could have an outsized effect on how it performs in the test, even if the ESC works well.

“Due to its high cost and complexity, potential damage to vehicles, single available test facility, the influence of trailers and tires in the outcome of the test, the sine-with-dwell is unworkable with heavy-duty tractors,” Blubaugh said.

Representatives of Navistar Inc., Volvo Trucks North America and Daimler Trucks North America agreed with Blubaugh’s conclusions.

“Preventing events that do not occur in the real world provides little benefit to customers,” said Jacqueline Gelb, director of government relations at Navistar. She said that if a truck made the turns necessary for a sine-with-dwell, it probably would leave the roadway, which ESC cannot prevent.

The test is also easy to fool, Gelb said. Navistar has performed the test on a truck with ESC disabled, and it passed.

“The sine-with-dwell test is a very expensive test to perform and will add incremental costs,” Gelb said, adding that the costs would be passed on to carriers, shippers and, ultimately, to consumers.

For Volvo, the additional testing is unnecessary because testing also already has proven ESC’s effectiveness, said Tim LaFon, manager of regulatory affairs for the company, which includes Mack Trucks Inc.

“We’re just trying to understand the value of doing additional testing,” he said. LaFon also was concerned about selling a truck that has gone through sine-with-dwell.

Nasser Zamani, senior manager of regulatory affairs for Daimler Trucks North America, said

that the sine-with-dwell requirement would be “burdensome, destructive to our business practices and unworkable.”

Zamani estimated that it would add millions of dollars of unnecessary costs for Daimler. Those costs would be passed on to customers, he said.

Apart from the testing objection, all the truck maker representatives said they supported the ESC mandate.

But Ted Scott, director of engineering for American Trucking Associations, said his group is asking NHTSA to require only the less-expensive rollover stability control. Fleets could have the option to add electronic stability control if they want ESC, Scott said.

“ATA is not convinced that ESC’s effectiveness advantage is significant enough to mandate only the ESC system for an industry that is as diverse as this one,” he said.

Different segments of the industry have very different needs, and Scott called NHTSA’s proposal a “one-size-fits-all” approach.