Dyno Might?

by John G. Smith

TORONTO, Ont. – The group behind North America’s roadside inspection blitzes will be asked to investigate concerns about manufacturing standards that can unexpectedly leave truckers without trailer service brakes, Truck News has learned. Ontario Ministry of Transportation engineers will review a related OTA discussion paper prior to a November meeting of the Commercial Vehicle Safety Alliance (CVSA), as they prepare a bid to address the issue on an international stage.

“We want to see if we can get a handle on how big a problem it is,” CVSA president Peter Hurst told Truck News after a keynote speech during the annual conference of the Heavy Duty Distributors Council. “I’d like it to be addressed nationally and internationally instead of just here in Ontario. We’re working with the Canadian Trucking Alliance. We’ve asked the federal government, because they have the jurisdiction over the manufacturing standards, to come along and help us with this.”

The OTA has reported drivers can unexpectedly lose trailer service brakes built to meet Canadian Motor Vehicle Safety Standard (CMVSS) 121, a federal manufacturing standard that is largely a duplication of its American counterpart. Under the rules, spring brakes cannot apply or drag if trailer brakes lose air pressure. But air compressors can keep up with leaks caused by such things as flying road debris that damages an air tank’s drain valve. Air gauges won’t reflect the loss of pressure, and drivers will have no indication of a problem until they apply the service brakes.

Issues raised in Ontario could be seen as having added weight on the alliance’s agenda since Hurst is also director of carrier safety and enforcement at the Ontario Ministry of Transportation.

Ontario has the most at stake because the problem can be magnified in multi-axle “Michigan combination” trailers that are widely used through the province. Almost half of Canada’s trailers have three or more axles, compared to the three per cent of U.S. trailers that ride on anything more than a tandem.

The CVSA, meanwhile, is also trying to determine the reason behind a “significant difference” between the number of brake defects found during an unannounced inspection blitz in May, and the widely publicized annual Operation Air Brake on Sept. 5, Hurst says.

In September, 11 per cent of the 14,665 inspected units had brakes that were out of adjustment, with just over 16 per cent of brakes out of service. In May, 13 per cent of the units had brakes that were out of adjustment, and 18 per cent of inspected brakes were out of service.

Brakes seem to be at the top of Hurst’s mind. His ministry staff is also investigating the use of Performance Based Brake Testers (PBBTs) that can offer a true indication of a truck’s stopping power.

One of the biggest questions is what officers will do when the distance between chalk markings on a pushrod – the traditional test of brake adjustment – and the high-tech reports of a PBBT disagree.

“The potential is there (for a discrepancy),” Hurst admitted to Truck News. “We don’t know what we’re going to see.”

Jurisdictions such as Minnesota have already introduced the equipment at roadside inspection stations. And more than 30 testers can be found in shops that perform annual equipment inspections in Quebec.

“It’s probably important for us to go beyond the chalk and ruler process if we’re really interested in performance – in other words, the ability for a vehicle to stop safely,” says Al Tucker, executive director of the Heavy Duty Distributor Council and the Canadian Transportation Equipment Association. “We’re not sure the chalk mark on the pushrod is doing it.”

While the days of chalk and ruler as the ultimate test of brake performance may be numbered, don’t expect a shift overnight.

Says Hurst of the timeline, “I would say we’re talking about five years.”

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