How bull bars/steel bumpers can make your car/SUV’s airbags useless/ineffective

A lot of cars, most of them brand new, are fitted with bull bars/guards. Then we have SUV owners adding butch-looking steel bumpers in place of the fiber ones. These simple accessories may actually prevent your car/SUV’s airbags deploying incorrectly, making the vital safety feature useless. Here’s how.

To understand how bull bars and steel bumpers can interfere with airbag deployment, we first need to understand how an airbag is deployed.

An airbag takes input from an inertia sensor (accelerometer), called the airbag sensor. The airbag sensor is mounted at the front of the vehicle. While it may be placed behind the front bumper in many cars, some have this sensor behind the headlamp or even the radiator.

The airbag sensor either features a ball/cam. The ball/cam keeps moving during the normal course of driving but does not complete the airbag circuit. In case of an impact, the ball/cam triggers the circuit, causing the airbags to deploy.

Different car makers use similar but different algorithms that determine the deployment of airbags. This makes the addition of bull bars/steel bumpers that are not car maker-designed even more complicated as the after market manufacturers may not have access to the design parameters of the vehicle.

Where does the steel bumper/bull bar come in?

Now, when you add a steel bumper or bull bar that is not designed to work with a vehicle featuring airbags, there is a chance that these accessories may affect the triggering of the airbag circuit. For instance, steel bumpers are way more solid than fiber ones, which are designed to crumple. Therefore, steel bumpers may make the crumple zones redundant and affect the algorithm that triggers the deployment of airbags.

If improperly triggered, the airbag may deploy earlier or later. Both cases are dangerous. If deployed early, the frontal airbag can snap the driver/passenger’s neck by pushing the head of the person behind at a very high speed. If deployed late, the airbag will fail to protect and the head of the driver/passenger could collide with the steering, causing grievous injuries or even death.

So, how do you make sure that the steel bumper/bull bar is airbag friendly?

While adding bull bars/steel bumpers that is not certified to be used in an airbag equipped vehicle is dangerous, some of these accessories are approved by automakers. Toyota approves some bull bars that can work with its vehicles while other aftermarket bumper makers such as ARB certify that their steel bumpers will not impact airbag deployment. So, buying an airbag friendly bull bar/steel bumper is very important if you value your safety.

The insurance angle

Now, suppose you’re in a car/SUV fitted with a bull bar/steel bumper, and that has had an accident. Assume that the airbags deployed during the accident, the insurance company may still deny your claim as the accessory fitted was not approved by the RTO. This is one more reason why bull bars/steel bumpers can be more harmful than useful.