Now that we have established that is quite unlikely to have a brake failure due to the construction of the braking system and that is relatively simple to stop a car just by using the rolling resistance, it’s time to analyze some other methods of stopping the car without brakes. Please be advised that the following methods are more dangerous than the first ones and by using them you may destroy some components of your car.
The first thing you should do is call the highway police. Announce them that you have a problem and that you can’t stop the car. They should give you some assistance and even guide you throughout the stopping process. In the worst case scenario, they will help you to stop by contact with one of their vehicles. Don’t worry for damaging the car. That’s why you have insurance for. And keep in mind that your life is far more important than a piece of metal.
If your situation is desperate and you can’t have assistance from the police, here is another destructive method of stopping the car without brakes is by using the engine. But it is not that simple. For manual transmissions you should kill the engine and after that you should select a gear and release the clutch. Go from high gears to low gears as the speed decreases. By doing so, the engine transforms form a motor into a compressor and its added resistance should be able to stop the car more rapidly. This method can destroy some components of the engine so try to use it only for emergency cases. For automatic transmissions this procedure can be a little tricky because the computer behind the transmission has a mind of its own and can deny you the gear change. So, with the engine running, go into the manual mode for your transmission and try to “overwrite” the gears by selecting them from high to low until the car is moving slower. Then, with the engine stopped, put the shift stick in P (Parking) mode and hope for the best. In the parking mode, a bolt locks the shaft of the transmission and by engaging it while the car is moving can either destroy the bolt or the transmission. But you should be safe as after decreasing the speed using the gears shift method.
The third destructive method is by purposely crashing the car. Be advised that this is a very dangerous method and should be executed only as a last measure. On most roads and highways there are side barriers. They are purposely designed to absorb a large quantity of energy in order to prevent a car going on the wrong side of the road. If your brakes failed, you can use this feature in your advantage. You can purposely grind the side barriers with your car and by deforming them you transfer energy from your car thus reducing the speed. Be very careful when executing this kind of maneuver because it is very easy to lose control. Also, try not to put the other road users in any danger what so ever.
As a already said, this kind of situation is pretty unlikely considering how safe are the modern cars, but, in case it does happen, now you know what to do.