Canada raises underriding concerns

In 1998, the National Highway Traffic Safety Administration culminated a decades-long debate over how to protect motorists who crash into the rear of trailers.

The design of rear bumpers for trailers had been argued off and on almost since the old Interstate Commerce Commission created the ICC bumper in the 1950s. Some may have thought that the issue was settled after NHTSA's underride regulations became final almost six years ago.

But final rules aren't necessarily final, and debate never really has stopped. This includes questions raised by trailer manufacturers, whose job it is to deliver compliant guards to the marketplace. In particular, manufacturers of specialized trailers have continued to ask NHTSA for clarification and for some minor changes intended to fine-tune the regulations to the environment in which underride guards are installed and to the conditions in which they operate.

In recent months, though, underride has once again moved to the regulatory forefront. In October, Transport Canada published its new underride regulations. In November, NHTSA kept the Federal Register printing presses busy with no fewer than three new final rules that modify FMVSS 223 and 224.

NHTSA may have produced more final rules, but it is Canada's new rear underride standard that promises to send U S and Canadian engineers back to the CAD station.

While many of the requirements mirror U S regulations, the Canadian standard substantially raises the bar (figuratively speaking). For example, the new Canadian regulation requires underride guards to resist at least 350,000 newtons (78,680 pounds) without deflecting more than 125 mm (4.92 inches). As an option, the guard can be tested without considering the amount of energy it absorbs. But if it is tested without regard to energy absorption, the guard must withstand a 700,000-newton load (157,360 pounds).

The difference between the Canadian and U S requirements for energy absorption is huge.

“Where energy absorption is required, the guard must be capable of absorbing the equivalent of at least 20,000 joules of energy by plastic deformation within the first 125 mm of deflection,” according to the Oct 6 Canada Gazette, “an amount 3.5 times the U S minimum of 5,650 joules.”

In addition, the Canadian standard requires the guard to remain no more than 560 mm (22 inches) above the ground after the uniform load test is completed.

The Canada Gazette notice said that Transport Canada tries to maintain uniformity between U S and Canadian regulations in order to facilitate trade between the two neighbors and to reduce the regulatory burden. But according to the Canada Gazette notice, the Ministry of Transport made the underride regulation more stringent than NHTSA's because smaller automobiles are more common in Canada than in the United States. Subcompacts represent approximately 12% of the Canadian market, compared with about 2.5% in the United States.

Effects of the new regulation are being felt in both countries.

In Canada, the higher standards have the Canadian Transportation Equipment Association (CTEA) taking a new look at its innovative underride guard program. CTEA and Canada's National Research Council teamed up to produce an underride guard that could be used by multiple trailer manufacturers. The idea behind the generic underride program was to enable Canada's small manufacturers — those that may not have the resources to design and test their own underride guard — to obtain one that meets existing applicable standards. The generic guard, however, was designed for existing U S regulations, not the new Canadian measure.

The law becomes effective next year. When it does, manufacturers will have the option to build to U S or Canadian standards. That option expires Sept 1, 2007, when trailers will be required to meet the more stringent requirements. Details are available from CTEA (, or the rule can be read by visiting

Some Canadian trailer manufacturers argued that the proposal would put them at a competitive disadvantage against U S trailer manufacturers that do not have to build an underride guard to the higher standards.

We would argue that over the long term, trailer manufacturers that build to the higher standard — regardless of nationality — will have the advantage. Stronger, more expensive guards may or may not be a selling point in the marketplace, but they will be a huge advantage in the courtroom. The real disadvantage will belong to the trailer manufacturer who has to explain to a jury why he used a weaker underride guard when a stronger one was available. And the advantage will go to the manufacturer that builds to higher standards.

TAGS: Trailers
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