Which of the following factors has the greatest effect on the motorcycle braking distance when riding in good weather conditions?
Show the correct answer
Correct answer
B. The speed at which the motorcycle is moving.
Explanation
In the photo a motorcyclist is riding along a street in town through a gentle curve, in good conditions, during the day. In such conditions, the length of a motorcycle's braking distance is affected most by the speed at which you are riding - answer B.
The Road Traffic Act requires you to ride at a speed that ensures control of the vehicle, and braking distance is the most important reason for this rule. The energy of motion grows with the square of the speed: twice as fast means a braking distance four times longer, so on a good road surface and with working brakes, it is the speed that decides where you stop. The rider's reaction time (answer A) lengthens the stopping distance - the section you travel before you even start braking - but not the braking distance itself, which is counted from the moment you press the brake. Clothing (answer C) protects you in a fall, but has nothing to do with braking. In practice: from 50 km/h a motorcycle on dry asphalt stops within a dozen or so metres, and from 70 km/h it already needs about twice as much. By slowing down by 20 km/h in town, you gain a dozen or so metres, which decide whether a pedestrian lives.
Legal basis: Art. 19 para. 1 of the Road Traffic Act (Prawo o ruchu drogowym)