If for any reason you have to do a stop without using your foot brakes, firstly you would slow down using your gears if time allows this, if this does not bring you to a halt, and it often will, you could very gently apply the handbrake, you would aim to do this on a very straight piece of road and avoid turning the steering wheel as this could put the car into a spin as mentioned above.
However, if you are driving a Landrover or similar vehicle, the handbrake is connected directly to the drive shaft, applying the handbrake on these vehicles under such circumstances would probably mean buying a new gearbox
A slight impact would be advisable over a head on impact, so i would probably advise, using a crash barrier and driving up against it or even driving up against a wall or a hedge to slow down would be preferable to a head on with anything.
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