Driving Dynamics, Vehicle Technology and Safety Equipment
Physics questions reward understanding of stopping distance = reaction distance + braking distance. Reaction distance grows linearly with speed (about 1 m per km/h at one second reaction), braking distance grows with the square of speed. Doubling speed roughly quadruples braking distance. Friction depends on tyres, road surface and weather; wet roads roughly double braking distance, ice can multiply it many times.
Understand ABS (prevents wheel lock, keeps steering), ESP (stabilises the car by braking individual wheels), ASR (traction control), brake assist, and tyre labelling (wet grip, rolling resistance, noise). Know that ABS does not shorten braking distance on loose surfaces and that ESP cannot overcome physical limits. Load and centre of gravity affect cornering and braking; roof loads raise the centre of gravity and increase rollover risk. Tyre pressure and tread depth (minimum 1.6 mm, 4 mm recommended for winter) are frequent test items.
Traps: confusing reaction time with braking time; assuming four-wheel drive shortens braking distance; forgetting that ABS allows steering while braking but requires firm, continuous pedal pressure.
Worked rule of thumb: at 50 km/h with one second reaction, reaction distance is about 15 m; normal dry braking adds roughly 12–13 m, giving a stopping distance near 27–28 m. In rain, plan on roughly double the braking part.