Should you replace the driver’s seat belt after an accident?Absolutely. In fact, the seat belt for all occupied passengers should be replaced as well.

My daughter was recently rear-ended by a 90 year old woman who could not walk without the aid of a walker.As a result, we had to get an estimate for the repair of the rear bumper.

USAA (the lady’s insurance) recommended I take the car to Caliber Collision. The experience wasn’t very good, mostly because the estimator refused to include a quote for the seat belt replacement. Instead, she went out of her way to put on the quote that no airbag light is on, no airbags deployed, and seat belt still functioning. This is certainly not what you would call customer care. Rather, it seems she’s trying to help USAA save money.

First, airbags are designed to NOT deploy in a rear end collision. If you are hit from behind the airbags just don’t deploy. Even if you are pushed into a car in front of you, there’s a good chance the airbags will still not deploy.

So what does the failure of the airbag tell is in a rear-end collision? Nothing. Of course, you wouldn’t expect the airbag light to come on either.

So that leaves the “seat belt still functioning” argument. Of course, the set belt appears to function. Just like the rear bumper appears to function, but there might be hidden damage under the bumper which would put the occupants at risk in the event of another crash.

In terms of the seat belt, the harm may not be visible to the naked eye. Here’s what the government of Western Austalia’s Department of Transport says in bulletin IB-113B:

You should replace a seat belt if there is evidence:

• Of nicks on the webbing or other webbing damage
• Of excessive wear and tear which comes with age
• Of a malfunctioning buckle, retractor or fittings
• That a particular seat belt was in use during a crash.

If your vehicle is involved in a serious crash, you should consult with your car repairer as to whether to replace all seat belts that were occupied at the time.

You should always replace the driver's seat belt vehicle after it has been involved in a serious crash. You should also replace any other occupied seat belt in the crashed vehicle. It should be appreciated that damage to webbing and mechanism is often invisible to the eye.

…

A cut as small as 5 millimetres can reduce the performance of a seat belt significantly.

…

Seat belts are important safety devices that are designed to work effectively only once. Therefore seat belts that were occupied in a significant crash must be replaced.

The webbing is designed to stretch without breaking in order to absorb deceleration forces in a crash. Once the webbing has been subjected to the forces resulting from a crash it is usually stretched permanently and loses its vital elasticity.

If used in a subsequent crash the webbing may not stretch as originally designed and thereby can cause serious injury by increasing the risk of chest, neck and back injuries to the occupant.

Besides the webbing, the retractor and buckle assemblies should not be relied upon to function correctly again after crash forces have been applied to them.

Some vehicles are fitted with pretensioners or Pyrotechnical Buckle Pretensioners. These pyrotechnic devices, which pull the seat belt tight at the time of a crash, can only function once and must then be replaced.

If a pyrotechnic device has fired then the seat belt stalk cover will be deformed and the buckle will sit low on the seat. The entire seat belt assembly must be replaced.

So yes, I think that any occupied seat belt should be replaced after a crash, just like you would for a baby seat.