Atlanta, GA- In 2011, over 250 people were killed in accidents where their vehicles were pushed under a tractor trailer and an additional 5,000 were injured according to the Insurance Institute for Highway Safety who is advocating for tougher federal standards for underride guards to prevent potentially fatal truck accidents.

Underride guards are those metal bars that hang from the back of tractor trailers. These guards are intended to keep passenger vehicles from sliding under the rear of a tractor trailer. The federal government began requiring that semis and tractor trailers have underride guards in 1952 and in 1998 those requirements were strengthened.

But the IIHS thinks those standards should be tougher after conducting separate crash studies in 2010 and 2011. Although the studies showed improvement in underride accidents the IIHS believes that many of these guards were too flimsy or inadequate enough to keep cars from sliding under the rear of tractor trailers.

The crash studies revealed that when a car hits the rear of a truck straight on, the underride guard will keep the car from sliding under a tractor trailer. However if the impact is either right or left it the truck’s center, the guards fail to prevent fatal underride accidents, according to the New York Daily News.

If the guards bend of break the vehicle’s safety structures, the windshield becomes the point of impact. In these cases, airbags fail to deploy and seat belts cannot serve their intended purpose causing more damage to a vehicle and leading to fatal or serious injuries to motorists.

“When an under-ride guard fails, it’s a very devastating crash. The first point of impact is on the windshield. Then the top of the passenger compartment is sheared off.” says David Zuby of the IIHS.

After the 2010 and 2011 IIHS studies, they petitioned the NHTSA to pass more stringent standards for underride guards. When they released the results from their third study in May of this year they noted that the NHTSA never responded to their initial petition for tougher standards and release the result of a separate study which was conducted by the University of Michigan.

In a formal statement NHTSA said: “Moving forward, results from the field analysis, IIHS’s tests, international standards and other data will be leveraged by NTHSA and may inform potential changes to existing federal safety standards — including more stringent rear-impact guard requirements — based on what all the data show.”

While there are no new federal standards for underride guards some truck manufacturers are making stronger, sturdier guards that can withstand greater impacts.

Some safety advocates would also like to see tractors trailers with side undderride guards. Accidents were a vehicle is pushed under a tractor trailer from the side which is just as dangerous and deadly as going beneath a truck from the rear. Side undderride guards are a requirement in many European countries but there is no such requirement in the states.

The trucking industry has resisted retro-fitting there vehicles with stronger undderride guards and will likely pushback against any new standards.