The Case Against Anti-lock Brakes

on Jan 19, 2010

Anti-lock brakes (ABS) are touted as a safety feature on cars. They work to solve the problem where excessive braking force causes the friction between the brakes and the wheels from exceeding the friction between the wheels and the road (without ABS, the brakes lock the wheels in place so that the wheels slide on the ground which in turn prevents braking and turning – rather dangerous). ABS “prevents” this from happening by reducing braking force when it senses the brakes have locked.

However, ABS introduces its own set of dangers and other disadvantages. First, the function of ABS can be misinterpreted. Although ABS prevents the car from skidding when too much braking force is applied, it do not increase braking power. Braking power, ABS or not, is limited by the amount of grip between the tires and road. This fact is not clear to many drivers nor is it one stated by those touting ABS.

Second, a danger lies in risk compensation - where having ABS gives drivers a falsely sense of security, causing drivers to drive with less care. Drivers who don’t have ABS, on the contrary, may have a very real perception of how dangerous conditions can be; often from experiencing their brakes locking. The non-ABS driver prevents locking by carefully applying pressure to the brake pedal, which requires the driver to be well aware of the road conditions. This awareness, needed by non-ABS drivers to judge maximum braking force, is not needed by ABS drivers which causes them to be less respective of dangerous driving conditions. Remember: there is no difference in braking power between ABS and non-ABS cars. The very nature of ABS is that it allows for safety after the danger point (too much braking in dangerous conditions) has occurred while the nature of non-ABS requires preventing such a situation from occurring. We already know that we’re better off preventing problems than treating them after allowing them to occur.

Third, ABS adds complexity to the vehicle – something could break (there are redundency systems in place – even more complexity!) and it adds to the cost of the car. This makes little sense if the technology doesn’t realistically improve safety.

Unfortunately, drivers in the US no longer have a choice on ABS because it is a standard feature, by law, on all new cars. Still, I believe ABS can be a very useful technology if used mindfully and with a proper understanding of its limits along with regard for road conditions.

What do you think about ABS?