Driving Reaction Time Test
Brake when a hazard appears — then see your real stopping distance.
Your reaction has a distance
Your car carries on at full speed for as long as you take to react, all before the brakes contribute anything. That is thinking distance, and it scales directly with speed: 100 km/h means nearly 28 metres every second, so a 250 ms reaction burns almost 7 metres before you touch the pedal.
At 50 km/h on a residential street, that same 250 ms reaction eats about 3.5 metres. At 130 km/h it runs past 9 metres before your foot even moves, which is why an identical lapse in attention grows more dangerous the faster you travel.
Braking distance gets added on top for real stopping distance, but the thinking part is the only piece reaction time governs, and it is why staying alert behind the wheel counts for so much. Head to the average reaction time page to see how your number stacks up.