Fleet Management

IIHS Tests Show Clear Safety Benefit of Side Underride Guards

May 10, 2017

SHARING TOOLS        | Print Subscribe

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.


  1. 1. Wade Groen [ May 10, 2017 @ 10:58AM ]

    Yep just what we need,..... more weight added to our class 8 vehicle reducing the amount of overall freight we can move with our equipment forcing shippers to reduce max load volumes and decrease efficiency of how freight moves in this country. Why is it the responsibility of the commercial vehicle owners to add cost and weight to their equipment to protect a motorist that wasn't paying attention. Let remember that over 80% of motor vehicle accidents that involve a commercial truck are caused by the motorist in the car not by the truck!

    Sounds like this manufacturer of this side under ride guard will do anything they can to get lawmakers in their pocket to push their product on commercial truck owners through a mandate. WE NEED LESS MANDATES AND MORE EDUCATION FOR STUPID MOTORISTS!!!

  2. 2. wade [ May 11, 2017 @ 06:05AM ]

    Continuing to make roads safer....? You haven't answered the question of why impose a mandate on the commercial vehicle owners..? Is it because you assume their pockets are deep and they will once again absorb an insane mandate as suggested here..? Why is further and better education for motorists not a mandate upon receiving their drivers license?
    This is 100% an effort to pad ones pocket with a mandate forcing truck owners to buy your product. Wouldn't it be so easy for other start up companies to become widely successful with guaranteed income due to a mandate of the use of their product..

    Once again over 80% of accidents involving trucks are caused by the 4 wheeled vehicle not the truck. Educate those who cause the accidents!

  3. 3. Steve [ May 11, 2017 @ 07:33AM ]

    You are Right Wade why is it always the Trucking Industries Job. to save the lives of everyone else. If these and everything else that is Mandated should be paid for by the Idiots that cannot be Educated. Why is it always the Trucking Industry's Problem to protect stupid people.

  4. 4. RG [ May 11, 2017 @ 09:44AM ]

    Great Idea! And since the insurance companies will benefit by million$, they should pay for the 'bumpers'.....

  5. 5. Michael [ May 14, 2017 @ 01:06PM ]

    Looks like someones funded another study to confirm the obvious. Hmmm, what happens if a car with a hood 30" tall hits the side of a truck with a trailer side that 45" tall? Do you think the car will go under the trailer? Perhaps a few hundred thousand dollars can confirm this hypothesis.

    I must agree with the previous comments. I think it's time to stop relying on truckers to compensate for untrained and unobservant drivers with more technology and equipment. Maybe this is what Darwin meant by "natural selection".

  6. 6. Peter [ May 15, 2017 @ 06:18AM ]

    I feel that we are protecting drivers from their own bad behavior then to correct the problem.

    Root cause will substantiate that drivers are taking more chances, possibly because their vehicles are better built and are technologically smarter,, instead of learning good driver behavior.

    I feel people should be tested with both written and driving tests each time they renew or every 5 years. The driving tests should include, backing (parallel, driver and blind side), traffic circle travel, and a total of 1/2 hour of on road observance from an official. The cost to the person might be over $150.00 per test, but think how this would lower crashes and injuries?

  7. 7. Doug [ May 25, 2017 @ 06:54PM ]

    Maybe insurance should be forced to give commercial vehicle owners reduced rates for installing these safety props.


Comment On This Story

Comment: (Maximum 2000 characters)  
Leave this field empty:
* Please note that every comment is moderated.


We offer e-newsletters that deliver targeted news and information for the entire fleet industry.


ELDs and Telematics

sponsored by
sponsor logo

Scott Sutarik from Geotab will answer your questions and challenges

View All

Sleeper Cab Power

Steve Carlson from Xantrex will answer your questions and challenges

View All