Opinion: A back to school primer on safety

There are some basic laws at play every time we drive a vehicle – and they aren't just the ones enforced by police.

As Chilliwack students stream back to school this week, parents (and motorists in general) should do a little homework.

One of the most important subjects worthy of review is basic physics.

Too often we forget that the vehicles we travel in are enormous chucks of metal that when travelling forward require a huge amount of energy to stop.

The bigger the mass and the faster the speed, the more time and energy is needed to stop it.

An average vehicle travelling 50 kilometres per hour, for example takes 13 metres to stop once the brakes have been fully applied. A vehicle travelling just 10 kilometres faster takes 20 metres to stop.

And that’s just the braking time under dry condition. What also increases is the reaction time.

Combined, the stopping distance between vehicles moving 50 or 60 kilometres per hour can be a difference of 20 metres.

Most school zones limit speeds to 30 kilometres per hour.

And there’s a reason.

At that speed, the stopping distance (reaction and breaking combined) is roughly 17 metres.

But there’s more. When young bodies are hit by vehicles, they are more likely to suffer life-threatening or life-altering injuries, says Safe Kids Canada.

And the faster the speed at impact, the more severe those injuries will be.

Indeed, for a pedestrian hit at 30 kilometres per hour, the survival rate is around 95 per cent.

Double the speed to 60, and the survivability drops to just 10 per cent.

Consider this: Two drivers notice the same pedestrian in the road 37 meters away. One is travelling at 30, the other is at 70. The one doing 30 has plenty of time to stop. The driver doing 70, however, will likely hit the pedestrian at 43 kilometres per hour.

Today’s vehicles have been built for comfort. The ride is smooth, and speeds are easily disguised.

Braking has been improved, airbags and seatbelts installed. Even onboard computers that can detect objects in our path.

What hasn’t changed is the basic physics under which all these vehicles operate.

And managing those physical laws requires drivers who are aware their surroundings, and cognizant of their vehicle’s limitations.