Side Underride Accidents and Guard Nonuse as a Basis for Liability in Truck Litigation

What is a Side Underride Accident?

A side underride accident is a wreck between an 18-wheeler and another vehicle where the vehicle collides with the side of the 18-wheeler and goes under the trailer of the truck. This type of accident often results in the sheering of the top of the other vehicle and can result in serious injury including the decapitation of the occupants of the smaller vehicle.

What Are Side Underride Guards?

truck with side underride guardSide underride guards are devices that may be mounted on trucks to prevent vehicles from going underneath an 18-wheeler trailer in a side-impact crash.  Side underride guards protect bicycles and pedestrians as well. Side underride accidents involving cars typically happen in one of two ways: 1) a car goes head-on into the side of a truck at an intersection, or; 2) the truck makes a turn unaware someone is sitting beside the truck. Side underride guards come in several shapes and sizes, but the gist is that steel is placed in such a way as to prevent things from going under the trailer in a side-impact crash. They operate the same as rear underrides but only down the sides of the truck.  Rear underride guards have been required by law since the 1950s to prevent the same effect in a rear-end impact.

Should Side Underride Guards be Required on 18-Wheelers?

The debate as to whether trucking companies should be required to use side underride guards in order to prevent side underride accidents has garnished significant attention in the news as of late. New proposals to reduce the commercial truck driving age could mean more inexperienced drivers on the road—and this could mean more accidents. Side underride guards are not currently required by any Federal Law even though rear underride guards are. Despite this, the failure to implement these devices could very well be a basis of liability in future truck accident cases involving a side underride crash.

More Inexperienced Truck Drivers Mean More Side Underride Accidents

Inexperienced truck drivers are more likely to miss a vehicle to the right or left and make an unsafe turn leading to more side underride accidents. Between an ever-growing trucking industry in the United States and the large number of baby boomers hitting retirement age, the trucking industry anticipates the need for 89,000 new drivers per year from now through 2025 according to a report by the American Trucking Association.  There was a shortage of drivers required to meet the trucking needs by about 38,000 as of 2014 which is almost double that of 2005.  As a result of the ongoing shortage, the DRIVE- Safe Act has been proposed to reduce the interstate truck-driving age from 21 down to 18 to allow more people access to a career in interstate truck driving.  This creates the potential for many new inexperienced truck drivers to be on the road in the near future.  Inexperienced young drivers may be more likely to run red lights or turn when unsafe—both of which actions can result in side underride accidents.

What is the Debate Over Side Underride Guards?

The debate over side underride guards is a cost vs benefit argument. Side underride accidents are a small percentage of all accidents involving 18 wheelers. However, they do result in more serious injuries more often than other types of big rig collisions. As one might expect, the interstate trucking industry has a powerful lobby that may well have had a lot to do with why no laws or regulations have been implemented in the past on side underride guards. In 2015, the National Highway Traffic Safety Administration published a proposed regulation to upgrade rear-impact guard requirements. However, that proposed rule was never implemented.  A bill in the U.S. House of Representatives in 2017 entitled the Stop Underrides Act, was likewise stalled and never implemented. Recently, in March of 2019, the U.S. Government Accountability Office reported that more research was required to give proposals on rules. They did, however, throw regulation proponents a bone at the end of the report when they indicated: “with additional research on resolving the challenges associated with side underride guards, these guards may be closer to being a feasible solution than automated driver assistance technologies designed to prevent or mitigate side impacts that could lead to an underride crash.”

What Makes Side Underride Accidents Unique?

Two things differentiate side underride accidents from the typical truck accident case: the damages and the liability requirements. The damages in a side underride case often involve decapitation or death. This is because when a vehicle goes under the trailer of a truck, it typically does not fit. The roof may be crushed down or even peeled back. Intrusion into the cab is a common cause of occupant death or traumatic brain injury in these kinds of cases.

Second, side underride accidents are unique from the typical case that truck accident lawyers see in that the case may exist regardless of who was at fault for the collision.   In intersection collisions, either driver may have run a red light causing the wreck to occur. But the underride accident does not necessarily depend upon the truck driver causing the wreck since it is a failure to implement claim.

Are Side Underride Guards Required by Law?

There are currently no laws requiring 18-wheelers to install side underride guards. A bill dubbed the Stop Underrides Act was introduced in 2017 and again in 2019 in an attempt to require commercial motor vehicles to have side underride guards, however, the bills never became law. Despite the fact that several studies around the world have shown that side guards have the ability to drastically reduce fatalities in side-impact collisions with trucks, the American Trucking Association has fought against the Stop Side Underrides Act. Their voice is clearly loud enough to get heard.

Can Failure to Implement Side Underride Guards on 18-Wheelers Be a Basis for Liability?

As of now, no cases have held this. However, it is possible that the failure to use side underride guards could be the basis for liability in the future. In Stanley v. Star Transport., Inc., No. 1:10-CV00010, 2010 U.S. Dist. LEXIS 90404 (W.D. Va. Sept. 1, 2010), the failure to implement and utilize a crash avoidance system was a basis for liability.  Crash avoidance systems are control devices that make noise or give any warning when a vehicle is too close to another vehicle or swerves from its lane without a lane change signal (which may indicate a drowsy driver).  While this is not the same as a side underride guard, the law of this case could be used to establish that there was a safer alternative that the trucking company was aware of that may have prevented the damages done in a side underride accident.


Side underride accidents are not typical truck accident cases. They are essentially crash-worthiness cases—there was a safer alternative that the trucking company failed to implement. While there are no laws requiring side underride guards on 18-wheelers, trucking companies need to take note of the changing trucking litigation landscape and the potential for liability for not implementing side underride guards despite no laws requiring them.




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