Recently conducted tests by the Insurance Institute for Highway Safety have demonstrated the potentially life-saving benefit of placing side underride guards on trailers. As a result, IIHS contends that mandating such guards should be considered by policymakers.

IIHS said that comparing crash data on trailers with and without side underride guards in collisions with passenger sedans at 35 miles per hour shows that passengers are more likely to sustain fatal injuries when hitting a trailer without the guard. One test evaluated the AngelWing side underride protection device from Airflow Deflector, while a second test was on a trailer with only a fiberglass side skirt.

Without a side underride guard, the sedan wedged underneath the trailer, shearing off the roof and leaving passengers vulnerable to injury.

With the side impact guard, the sedan was prevented from going under the trailer, allowing the car’s airbags and safety belt to properly restrain the test dummy in the driver’s seat.

In both tests, a midsize car struck the center of a 53-foot long dry van trailer. The side underride guard was able to absorb the impact and bend without allowing the car to go underneath the trailer.

IIHS said a crash test showed that an AngelWing side underride guard stopped a car from going underneath the trailer. Photo: IIHS

IIHS said a crash test showed that an AngelWing side underride guard stopped a car from going underneath the trailer. Photo: IIHS

An IIHS study in 2012 found that underride guards have the potential to reduce injury risk in 75% of large truck side crashes producing fatality or serious injury to a passenger vehicle occupant. The proportion increased to almost 90% when restricted to crashes with semi-trailers.

"Our tests and research show that side underride guards have the potential to save lives," said David Zuby, IIHS executive vice president and chief research officer. "We think a mandate for side underride guards on large trucks has merit, especially as crash deaths continue to rise on our roads."

Asked to comment on the crash-test results and the IIHS contention that a side underride guard mandate should be considered, American Trucking Associations spokesman Sean McNally told HDT that the trucking lobby “believes the best way to prevent underride deaths is to prevent crashes in the first place, which is why our industry invests more than $9 billion annually in safety initiatives. Wider deployment of advanced vehicle safety technologies like automatic emergency braking and forward collision warning systems can help prevent all kinds of crashes, including those into the sides of trucks.”

McNally pointed out that ATA contends there are “complicating factors” to consider. He said that there are “engineering tradeoffs involving weight, strength, and effectiveness that have prevented a consensus around adopting side underride guards. For example, side underride guards would add significant weight and require stiffer trailers, which can develop cracks in the frame rails during normal operation – wearing out sooner and creating a safety issue of potential trailer failure during operation.”

He noted that “these guards are collision-mitigation – and not collision-avoidance – equipment and ATA’s primary safety goal is to prevent crashes. Avoiding the crash in the first place is even more effective than trying to manage the impact of a crash." McNally added that ATA is "working on several initiatives, including Electronic Logging Devices and other emerging crash-warning and avoidance technologies, that can help prevent all kinds of crashes.”

Federal law requires large trucks to have rear underride guards, but not side underride guards. At least three U.S. cities — Boston, New York and Seattle — mandate side guards on city-owned and/or contracted trucks as part of Vision Zero initiatives to eliminate crash deaths and injuries, particularly among pedestrians and bicyclists.

"With the rise of injuries and fatalities due to truck crashes, along with the need for greener technologies, Airflow Deflector's AngelWing side underride guards are an integral part of a long-term eco-friendly and cost-effective safety strategy that will benefit the public at large," said Robert Martineau, president of Airflow Deflector.