Pysähtymisnopeus

Pysähtymisnopeus, known in English as stopping distance or braking distance, refers to the distance a vehicle travels from the moment the driver perceives a hazard and decides to brake until the vehicle comes to a complete stop. It is a critical factor in road safety and is influenced by several variables.

The primary components of pysähtymisnopeus are reaction distance and braking distance. Reaction distance is the distance covered during the driver's reaction time, the period between noticing a hazard and applying the brakes. This time varies depending on the driver's alertness, concentration, and any impairing factors such as fatigue or alcohol. Braking distance is the distance the vehicle travels once the brakes are applied until it stops. This distance is affected by factors such as the vehicle's speed, braking system efficiency, tire condition, and road surface characteristics, including whether the surface is dry, wet, or icy.

Higher speeds significantly increase both reaction distance and braking distance. Due to the kinetic energy of a moving object being proportional to the square of its velocity, doubling the speed quadruples the braking distance. Therefore, maintaining appropriate speeds for prevailing conditions is crucial for ensuring adequate pysähtymisnopeus. Poor road conditions, such as wet or icy surfaces, can drastically increase braking distance due to reduced friction between the tires and the road. Similarly, worn tires or inefficient brakes will lengthen the distance required to stop. Understanding these factors is essential for safe driving and for calculating safe following distances.