You are travelling at 30 km/h. According to the rule of thumb, the braking distance is 9 metres when braking normally. How long is the braking distance under the same conditions when travelling at 60 km/h?

The braking distance increases significantly with speed due to the physics of inertia and kinetic energy. When you double your speed from 30 km/h to 60 km/h, the braking distance does not just double; it actually increases by a factor of four. This is because the stopping distance is proportional to the square of the speed.

At 30 km/h, the braking distance is given as 9 meters. When travelling at 60 km/h, the braking distance can be calculated as follows:

Braking distance at 60 km/h = 9 m * (60/30)^2 = 9 m * 4 = 36 m.

Thus, the correct braking distance at 60 km/h is 36 meters. This understanding is crucial in safely navigating German traffic laws, which emphasize the importance of maintaining a safe distance to react adequately to sudden stops. Understanding how speed affects braking distance is vital for all drivers to ensure they can stop safely and avoid accidents.