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Every time I go back to Edmonton to visit family, I’m shocked by all the tailgating. Other drivers sometimes get so close that I can’t see their headlights. It happens everywhere, but I always notice it there. Doesn’t the law there specify how close you have to be from the car in front of you? I always thought it was three car lengths. – Spencer, Vancouver

A close read of the law won’t tell you exactly how far you need be from the car in front of you. But you probably need to be farther away than you think, safety experts say.

Section 18 of Alberta’s traffic regulations says you can’t follow “more closely than is reasonable” for the speed, traffic volume and road conditions. If you are too close, it’s a $172 fine and four demerits.

What’s reasonable? As with most other provinces across Canada, including British Columbia and Ontario, Alberta doesn’t state a specific distance.

Well, it turns out the three-second rule doesn’t just apply to figuring out whether you can eat a French fry that fell on the floor.

“You pick a fixed landmark like a power pole, and once the car in front of you passes it, you count to three,” says Jeff Kasbrick, vice-president of government and stakeholder relations at the Alberta Motor Association (AMA). “If you pass it less than three seconds after they do, then you’re tailgating.”

That minimum three-second distance is for ideal conditions and for city speeds under 60 kilometres an hour, Kasbrick says. If you’re on the highway or if the weather is lousy, you should be increasing the distance.

Time to stop tailgating?

Generally, provincial driving manuals describe following distances in seconds – for instance, in B.C., Alberta and Ontario, manuals say to keep a two-second distance in good weather – instead of metres or car lengths.

Measuring in seconds works because it’s tough for most of us to estimate distances while driving. Plus, the safe following distance in metres or car lengths increases the faster you go. You need to keep more room at 55 km/h than you do at 50 km/h.

“If you’re going at a faster speed, you cover a lot more ground and you need more room to react,” Kasbrick says.

Driving instructor Ian Law recommends at least a four-second following distance even when roads are good. Most of us follow a lot more closely than that, Law says.

“There was an actual study where researchers stood on overpasses and timed the distance between vehicles – the average was 0.8 seconds,” Law says. “It takes the average human 2.5 seconds to realize something is wrong, figure out a solution and then react.”

More than close calls

In Alberta, tailgating is the top cause of crashes involving a death or injury, Kasbrick says.

“It’s about 3,200 crashes every year, or about nine per day,” he says. “It contributes to about a third of all collisions.”

It’s a similar problem across Canada, Kasbrick says. It’s also something you’re probably doing more often than you realize. An AMA survey found that 63 per cent of drivers said they often saw other cars following too closely. But, when asked whether they tailgated regularly, just 2 per cent said they did.

If you find yourself in front of a tailgater, don’t speed up dramatically or slam on the brakes, Kasbrick says.

“You don’t want to create a situation where there’s a chain reaction,” he says. “When it’s safe to do so, get into the other lane or pull over and let them pass.”

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