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Reflectors and speed in the dark

With dipped headlights you see a pedestrian in dark clothes at only about 25–30 metres. With a reflector you see them at around 140 metres. You should be able to stop within the reach of your lights. Work out how much time you have from seeing the pedestrian to reaching them, and compare it with your reaction time. Use main beam when you can.

Try it yourself

Speed in a bend and grip

t = \dfrac{s}{v}

the time from seeing the pedestrian to reaching them

Symbols

$s$	the distance at which you see the pedestrian	m
$v$	speed	m/s

Example

You are doing 80 km/h ( $v \approx 22$ m/s) on dipped beam.

No reflector: $t = 28 / 22 \approx 1.3$ s – barely time to react. With a reflector: $t = 140 / 22 \approx 6.4$ s – plenty of time to brake.

Wear a reflector yourself when you get out of the car in the dark, for example after a breakdown. Keep the hi-vis vest within reach of the driver's seat.

Practise winter, darkness and difficult conditions for free →

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Part of Car licence (class B): Winter, darkness and difficult conditions.