Rules of the road

Speed Limits & Following Distance

Default speed limits and safe following distance.

Know the default limits when no sign is posted, apply the two-second following rule in ideal conditions, and add more of both speed and space as conditions get worse.

A speed limit is the legal ceiling, not a target, and the same is true of the two-second following gap: both are minimums to adjust upward, never a fixed number to lean on.

Key facts

Where no speed limit is posted, the default maximum is 50 km/h in cities, towns, and villages, and 80 km/h elsewhere.
The minimum safe following distance in ideal conditions is at least two seconds behind the vehicle ahead.

Know the default limits

A posted speed limit sign always governs when one is present. Where none is posted, Ontario’s default maximum is 50 km/h in cities, towns, and villages, and 80 km/h on other roads. School zones and construction zones commonly post a lower limit for the length of the zone.

The posted or default number is a legal maximum, not a target: you must still slow further for conditions such as rain, fog, snow, or heavy traffic, even when the sign still reads the same number.

Apply the two-second rule

In ideal conditions, leave at least two seconds of following space behind the vehicle ahead. Pick a fixed point on the road, such as a sign or shadow; when the rear of the vehicle ahead passes it, count "one-thousand-and-one, one-thousand-and-two." If your own vehicle reaches that point before you finish counting, you are following too closely.

Two seconds is a floor, not a target distance. It gives you just enough time to see a hazard, decide, and brake under good conditions, which is why it must grow whenever conditions are not ideal.

Add space and reduce speed together

Increase your following distance beyond two seconds in bad weather, at night, in heavy traffic, or when following a motorcycle or a large truck carrying a heavy load, since any of these reduces your reaction time or the reliability of your view ahead.

Speed and following distance are linked decisions, not separate ones: reducing speed for a hazard without also increasing your following gap, or vice versa, undoes most of the benefit of either change.

Common mistakes

Treating a posted speed limit as a target speed rather than a maximum.
Keeping a two-second gap in rain, snow, or fog instead of increasing it.
Assuming an unposted road has no speed limit at all rather than the 50 or 80 km/h default.
Following a motorcycle or loaded truck at the same distance as a car.

Check your understanding

1. You are driving on a road in a small town with no posted speed limit sign. What is the maximum speed you may legally drive?

50 km/h: that is Ontario’s default maximum in cities, towns, and villages when no sign is posted.

2. How do you check whether you are following the vehicle ahead too closely in good conditions?

Pick a fixed point on the road; when the vehicle ahead passes it, count "one-thousand-and-one, one-thousand-and-two." If you reach that point before finishing the count, you are following too closely for the two-second minimum.

3. Why should you increase your following distance beyond two seconds in heavy rain?

Reduced traction and visibility mean you need more time and distance to see a hazard and stop safely than the two-second minimum provides in ideal conditions.