Speed increases braking distance

When drivers see an obstacle on the road, they react, put their foot on the brake and the car travels a certain distance before coming to a complete stop. This is called braking distance.

Speed increases impact

Speed greatly increases the severity of injury in the event of an accident. The risk of being seriously injured or killed from an impact doubles between 50 and 70 km/h and quadruples between 50 and 100 km/h.

• An impact at 50 km/h is like falling off a 3-storey building.
• At 75 km/h, it is like falling off a 7-storey building.
• At 100 km/h, it is like falling 12 storeys. 

Speed reduces traction

A speeding driver has a greater chance of losing control of her vehicle on turns, because of centrifugal force.

At high speed, the vehicle does not adhere to the road as well, and there is a greater risk of skidding.

Speed reduces your field of vision

Sitting still and at low speeds, a driver usually has a 180º field of vision.

At 100 km/h, the field of vision is reduced by half, because the human brain can only process a limited amount of data at once.

The greater the speed, the more visual information the brain receives, so it is forced to compensate by eliminating peripheral data.

A driver going very fast may not see a child about to cross a street or a car moving into the intersection.

Speed makes some emergency manoeuvres impossible

Passenger vehicles and especially trucks cannot stop instantly or make a 90º turn. As speed increases, the potential trajectories for avoiding an obstacle - such as a cyclist - are drastically reduced.

Car A is driving more slowly than car B.

Trucks are even harder to manoeuvre and slower to react than cars because they are bigger and heavier. Trucks need more space and time to brake than cars do.

More than 90% of a driver's decisions are based on visual information. 

10 km/h less can make a world of difference

A driver doing 50 km/h see a pedestrian... He has enough time to react, brake and stop if he is at least 31.2 metres away...with a reaction time of 1.3 seconds under normal conditions on dry pavement.

Let's repeat the example 10 km/h faster...

If the pedestrian is still 31.2 metres away when the driver sees him doing 60 km/h, the car will have slowed down, but will still be doing 42 km/h when it strikes the pedestrian. At this speed, the pedestrian will almost certainly be disabled for the rest of his life and may even be killed. At just 10 km/h less that pedestrian could go home safely...

According to some studies, a reduction of 3 km/h in average traffic speed would reduce the number of deaths and injuries by 15% annually.