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Why Aren’t Side Underride Guards Required by Law?

Why aren't side underride guards required by law

When you’re driving near a semi-truck, you’ve probably seen the metal bar attached to the back of the trailer that hangs lower to the ground. That’s called an underride guard, or more specifically, a Mansfield Bar, and attaches to the rear suspension of a semi’s trailer to prevent cars from slipping under the back of the truck after a collision.

This safety device was named after actress Jayne Mansfield, who died in 1967 when the car she was riding in rear-ended a semi-truck, killing her, her driver, and another adult due to their car slipping underneath the trailer. The bar was created after Mansfield’s crash to prevent similar devastating and deadly truck accidents from occurring.

So, if protective devices are such a good safety measure, and rear guards are already mandatory on all large trucks, why aren’t side underride guards required by law for semis?

We’ll dig into the details in this blog.

What is an Underride Accident?

Underride occurs when a smaller vehicle crashes into a truck and goes either completely or partially underneath it. This type of truck accident is incredibly dangerous for the driver and passengers of the smaller vehicle and often leads to serious injuries or death of those involved.

Evidence Supporting the Need for Side Underride Guards

According to data from the Insurance Institute for Highway Safety (IIHS), there were 2,495 passenger vehicle occupant deaths in crashes with large trucks in 2021, and 349 of those were side-impact accidents. This means that the passenger vehicle hits the side of the truck, which often ends up causing underride.

Tests of an aftermarket side underride guard, called AngelWing, have been performed since 2017 by the IIHS. The device attaches to the sides of a tractor-trailer, and a test with a midsized car traveling at 40 MPH showed that AngelWing successfully prevented the vehicle from sliding underneath the trailer.

More tests have been performed since, proving that, while side underride guards may not completely eliminate deaths in these crashes, they reduce the likelihood of an underride occurring.

Money Over Safety

The reason that side underride guards are not currently required by law is that it’s too expensive. That’s what it boils down to.

A 2023 report from the National Highway Traffic Safety Administration (NHTSA) suggests that if a side guard, such as the AngelWing system, is approved, the expected cost of installation (including labor and hardware) would be $2,990 in 2020 dollars.

By this estimate, the total cost of installing side underride guards on just the 260,000 new trailers sold annually would be approximately $778 million.

Not only is the cost of installation an issue, but the side guards can weigh from 450 to 800 pounds, requiring trucks to use more fuel since their overall load will be that much heavier. The increase in fuel usage is estimated to cost between $200 million and $430 million each year.

Why Aren’t Side Guards Mandated?

To answer the burning question: It’s considered too expensive to legally mandate side underride guards on semi-trucks.

But that might change, at least here in California and in New York.

As of January 2024, California Senator Scott Wiener proposed the Golden State adopt mandatory side underride guards on every truck, trailer, or semi-trailer with a gross vehicle weight of over 10,000 pounds. If passed, this law would apply to all affected trucks manufactured, sold, or registered within the state. A similar bill was proposed in the New York Senate.

According to data from the National Safety Council (NSC), California is one of the top three states for large truck accidents, resulting in the deaths of 437 individuals in 2021. Occupants of other vehicles made up 75% of those fatalities.

With these numbers in mind and the previous information about how important side underride guards are for the safety of smaller vehicles, it’s possible that these bills might be passed soon.

Here at Frost Law Firm, PC, we’re here to help with any questions regarding the laws surrounding the laws truckers and trucking companies must abide by. Additionally, our trucking accident attorneys are here to help you if a collision with an 18-wheeler here in San Pedro or elsewhere in southern California injured you or took your loved one’s life.

Our Experience Is Personal

Scott L. Frost’s Family Experience with Lung Cancer

For most of his life, Scott L. Frost’s father, who was in the construction industry, worked with and sold products containing asbestos without knowing the materials were dangerous. He was diagnosed with lung cancer 40 years after starting his career, leading Scott’s family to fight like they had never fought before.

Pictured here with his wife of over 50 years, Scott’s father eventually succumbed to the cancer. Since then, Scott has made it his mission to do everything in his power to make sure corporations understand how dangerous asbestos is and prevent future generations from suffering as his family did, as well as support research that may lead to finding a cure.

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