Jarrutusmatkan

Jarrutusmatkan is the Finnish term for the braking distance, the distance a vehicle travels from the moment the driver applies the brakes until the vehicle comes to a complete stop. It is one component of the total stopping distance, which also includes the reaction distance—the distance traveled during the driver’s perception of a hazard and subsequent reaction before braking begins.

The braking distance depends on deceleration. If v is speed and a is average deceleration, the braking distance is d = v^2 / (2a). Deceleration is limited by tire–road friction and the braking system. On dry asphalt a typical maximum deceleration for modern passenger cars is about 0.7–1.0 g (approximately 6.9–9.8 m/s^2). On wet roads it may be 0.4–0.6 g, and on ice as low as 0.1–0.3 g. ABS and other braking aids influence how smoothly and effectively the vehicle slows, but they do not guarantee a shorter braking distance in all conditions.

Other factors affecting Jarrutusmatkan include vehicle mass and load, tire condition and pressure, brake wear, the presence of electronic stability controls, road gradient, weather and temperature, and tire tread depth. These factors interact to determine the actual distance required to stop.

Practical implications are clear: braking distance grows rapidly with speed and worsens under adverse conditions. For example, at 50 km/h on dry pavement the braking distance is typically around 12–15 metres, while at 100 km/h on dry pavement it is roughly 40–50 metres. Wet or icy conditions can significantly increase the distance. Maintaining tires, brakes, and appropriate following distances helps mitigate risks.