Société de l'assurance automobile du Québec
Société de l'assurance automobile du Québec
Behaviours

Speed and the Laws of Physics

The laws of physics apply to everyone, even an excellent driver in a high-performance vehicle. The faster you drive, the greater the risk of an accident and the more severe that accident is likely to be.

Speed reduces the field of vision

The faster a vehicle is moving, the more information the brain receives. However, the brain can only process a certain amount of information at any given time, which means that at 100 km/h, it has to eliminate a large amount of peripheral information. The field of vision therefore decreases as speed increases.

Illustration showing that the faster a vehicle is travelling, the more the field of vision is reduced

Someone who is driving very fast may not see the little girl who is about to cross the street to retrieve her ball, nor the car that suddenly enters the intersection.

Speed increases braking distance

The greater the speed, the longer the braking distance.

The stopping distance more than doubles between 30 and 50 km/h, and nearly triples between 50 and 100 km/h.

Illustration showing that the faster a vehicle is travelling, the longer the braking distance

Speed increases the time required to carry out emergency manoeuvres

The faster you are moving, the harder it becomes to avoid obstacles. Driving more slowly makes it easier to avoid a cyclist who suddenly turns onto the road, for example. When driving faster, the possibility of avoiding the cyclist is reduced.

Illustration showing that the faster a vehicle is travelling, the more the trajectories to avoid an obstacle are reduced

Speed increases the risk of skidding out of control

Driving fast increases the risk of losing control of your vehicle, especially in a curve. The risk of skidding is greater at high speeds.

Speed increases the severity of collisions

In an accident, a vehicle stops abruptly and passengers who are not buckled in are thrust violently towards a point of impact (steering wheel, windshield, dashboard or another passenger). Even for those passengers who are buckled in, the speed at which the vehicle was travelling has a direct impact on the severity of the collision.

Illustration showing that the faster a vehicle is travelling, the greater the violence of a collision

An impact at:

  • 50 km/h is equal to a fall from the top of a 4-storey building
  • 75 km/h is equal to a fall from the top of an 8-storey building
  • 100 km/h is equal to a fall from the top of a 14-storey building

Last update: December 23, 2024