At 25 MPH it will take you about how many feet to stop a car?

Answer 1

The Uk Highway Code uses the formula:

[Emergency] overall_distance = thinking_distance + stopping_distance

with:

thinking_distance = speed_in_mph ÷ 1 ft/mph

stopping_distance = speed_in_mph² ÷ 20 ft/mph²

ie the thinking_distance is 1 ft per 1 mph, so at 25 mph, this would be 25 ft;

and the stopping_distance in feet is given by speed_in_mph squared divided by 20; for 25 mph this would be 25² ÷ 20 = 31.25 ft

So it takes about 31 ft (9.5 m) to stop a car from 25 mph.

Overall in an emergency it would take approx 25 + 31 = 56 ft (about 17 m), but the thinking_distance is very dependent upon the alertness of the driver.

Note: these formulae have not been updated for the improvements in car brakes, and the SAME distances are used when considering stopping a 23 tonne coach!