when your brakes fail, can you shift to Reverse in order to stop the vehicle? why or why not?

Question

I’m mostly thinking about a scenario where you are going down a highway (say, at 120kmh for the sake of the example) and suddenly your brakes fail

could shifting to Reverse function as a brake in that situation?

edit: thank you all for the answers, I want to note that I myself don’t drive and did not consider doing this, I was just wondering if this was possible

have a lovely day o/

In: 11

Answer 1

It depends on the type of vehicle and the transmission. The short answer is yes it’s possible in some cases but probably not the safest or most effective way to slow down especially at high speeds.

If you’re going really fast and driving a manual transmission vehicle you would be better shifting down through the gears one by one to bring your speed down before going into reverse, so that engine braking can take some of the speed out without damaging the car too much. By the time you got to 1st gear you should be able to get the speed down to about 40kph or less that way.

If you put the car straight into reverse you would be relying entirely on the friction in the clutch plate to absorb the kinetic energy of the moving vehicle, which at very high speeds would mean almost instant damage to the clutch because the vehicle is heavy and fast, so lots of energy, and the clutch plate is small and not very massive at all so it would end up getting very hot and deforming or fracturing.

In an automatic vehicle there’s usually a block on putting the it in reverse whilst moving forwards so it might not be possible to put the vehicle into reverse at all. If you were able to do it, similar would apply but you’d find it harder to downchange to lose speed before going into reverse and probably cause more expensive damage.

In either case, going straight to reverse might affect the steering making it more likely you’d go off the road or hit someone else, so it would be very dangerous.

A better strategy would be to stay off the accelerator so your vehicle is slowed by air resistance and try and direct your vehicle uphill if possible; you might be able to use the handbrake to absorb some of the energy once your speed had reduced.

But the best strategy here would be to maintain your vehicle regularly so the brakes don’t fail in the first place.