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


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

No, at best the car will stall.
Using the emergency brake, shifting to a lower gear/neutral, or just letting off the gas would probably be safer. At lower speeds, the e-brake or downshifting for engine braking would be ideal.

At 120kph, I would let off the gas and look for environmental things to slow me down (incline, terrain, etc). If all else fails, downshifting and e-brake.

You’d have a small time of stopping ability before your stalled engine would use its own resistance to slow you a little, assuming a fail safe didn’t knock it into neutral.

Automatic transmissions usually don’t allow to shift in reverse while the vehicle is moving forward. Manual transmissions would take damage when you shift the gears in the opposite direction, breaking gears without stopping the car.

However with manual transmission, just releasing the clutch and gas pedal, and maybe shifting down one gear before that, will engage engine breaking which is the regular friction of the engine. This has noteworthy effect.

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.

No, in a manual transmission you simply won’t be able to, the gears are turn the wrong direction. In an automatic when you are going faster than around 5mph a reverse inhibitor keeps the transmission from engaging reverse. What you should do is select a lower gear so the engine will slow you down. Downshift if you have a manual, or with an automatic many cars will let you select 1st and 2nd gear. Also you can use your emergency brake, that’s what it’s for, just be careful with it because it can lock your tires causing you to slide, be ready to release it if you lock your tires.