Trailer Talk

Truck and Trailer Side Guards Being Pushed and Sold

Blog commentary by Tom Berg, Senior Contributing Editor

December 21, 2017

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Side guards hang from a pup trailer's long tongue to keep "vulnerable road users" from blundering under it and being crushed by following wheels. Photos: Walker Blocker 
Side guards hang from a pup trailer's long tongue to keep "vulnerable road users" from blundering under it and being crushed by following wheels. Photos: Walker Blocker

There are moves afoot to publicize and perhaps require side guards for big trucks and trailers here in the United States. Truck side guards are designed to keep vulnerable road users—pedestrians, bicyclists, and motorcyclists—from being run over by a large truck’s rear wheels in a side-impact collision, according to the Volpe National Transportation Systems Center, a government-related research group.

Such devices work by physically covering the open space between the front and rear wheels of a truck. Side guards can also protect auto occupants by preventing a complete underriding of the truck or trailer.

Side guards have been talked about here for some time, and seem an offshoot of controversies over rear impact guards. For instance, the Insurance Institute for Highway Safety, long a critic of ineffective rear guards, has tested side guards and now advocates their use.  Last week two U.S. senators introduced a bill to mandate devices on certain vehicles.

The much publicized death of a Tesla Model S driver, who T-boned and underrode a semitrailer in Florida last year, was a prime example of an accident that might not have been fatal if the trailer had been equipped with sideguards. Of course, the accident wouldn’t have happened at all had the motorist tended to driving instead of enjoying the ride via the Tesla’s Autopilot (the news hanger here was autonomous vehicles – how safe are they? -- rather than underride accidents).

It’s true that side guards add weight and cost, and might never come into play in months and years of service. One could say the same about most safety equipment. But accidents do happen.

“Side collisions with large trucks were associated with 111 pedestrian and bicyclist fatalities annually in the U.S., based on 2005-2009 data on single-unit trucks and tractor-trailers,” says Volpe in a technical overview.  “Of the 75 fatal bicyclist crashes per year with trucks, approximately 50% were side impacts.”

The U.S. is behind other countries on this.

“Side guards have been required since the 1980s in the European Union and Japan, and more recently in China, Brazil, and Peru,” says Volpe. “Canada conducted research for a national side guard standard from 2009 to 2013 and also began evaluating the viability of using aerodynamic side skirts for vulnerable road-user safety.”

Evidently they work.

“Based on studies conducted in the United Kingdom, side guards are an effective technology for reducing the number of vulnerable road-user fatalities and the severity of injuries, especially for bicyclists," the overview says. "For example, in the UK, a 61% reduction in cyclist fatalities and a 20% reduction in pedestrian fatalities were reported in side-impact collisions with trucks following the national side guard mandate.”

American firms sense a need in the marketplace and have inroduced truck side guards. One is Morgan Corp., the body builder, which announced slat-type guards similar to those used overseas.

Side guard on a Chicago municipal stake-side truck protects pedestrians, bicyclists and auto occupants.   
Side guard on a Chicago municipal stake-side truck protects pedestrians, bicyclists and auto occupants.

Another is Walker Blocker, a new division of Allied Body, which was founded in 1947 in Seattle. It has supplied 13 sets of panel-type side guards to Seattle’s Department of Transportation and to other municipal fleets.

“We’re trying to stay ahead of the game,” says Seattle DOT’s fleet manager, Ricardo Sahagun. “We’re trying to increase safety for pedestrians and bicyclists. We encourage the use of bike lanes and for people to do a lot of walking around the city. Knock on wood, so far we haven’t had any accidents, but we have heard of incidents in other cities.”

Seattle DOT experimented with homemade metal guards on a pair of “attenuation” trucks, which carry large yellow impact guards to protect people and equipment in construction zones, Sahagun said. But they were rather heavy, so he obtained Walker Blocker devices for a dozen Ford F-series flatbed trucks and on a Kenworth T-800 mixer.

The guards have aluminum frames and composite panels, and are in several lengths to fit between varying wheelbases and underbody equipment of the trucks. The fleet paid about $15,000 for the 12 sets of Ford guards and $2,500 for the Kenworth guards, he said. They weigh 20 to 30 pounds each.

Seattle DOT's concrete mixer truck has a Walker Blocker side guard to close the gap ahead of the rear tandem's wheels.
Seattle DOT's concrete mixer truck has a Walker Blocker side guard to close the gap ahead of the rear tandem's wheels.

Side guards were also applied to the long tongue of a pup terailer pulled by a dump truck. But Walker Blocker has otherwise concentrated on trucks, said representative Doug Strauss.

The guards were built to meet and exceed Volpe's specifications, he said.  Volpe calls for strength sufficient to withstand 400 pounds of static pressure; Walker increased that to 650 pounds, and the test guard deflected but did not break.

“We are doing a pilot program with Portland [Oregon] right now and their garbage companies,” he says. “Garbage trucks are always around people and this past August a lady was killed in Portland by going under the garbage truck and being run over by the rear tire.”

Chicago and the District of Columbia have also mandated their trucks have the side guards, Strauss adds. Walker Blocker offers standard 2-, 3- and 5-foot-long guards and can build custom sizes. A brochure explains the products.

“If you want more of the history behind the side guard movement, please let me know,” he comments, “because this has been my life for the past year.”


  1. 1. Russ [ December 29, 2017 @ 11:56AM ]

    Shouldn't people just pay attention instead?


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Author Bio

Tom Berg

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Senior Contributing Editor

Journalist since 1965, truck writer and editor since 1978. CDL-qualified; conducts road tests on new heavy-, medium- and light-duty tractors and trucks. Specializes in vocational and hybrid vehicles.


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