What does the low clearance underpass warning sign mean?
Low overhead clearance ahead. Tall vehicles must check they will fit
This sign warns of an underpass ahead and shows the available clearance. The height shown is the maximum. Drivers of tall vehicles must make sure they will fit before continuing.
Why the other answers are wrong
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The minimum following distance is 3.9 metres
Following distance is measured in time, not metres: keep at least two seconds behind the vehicle ahead. The arrows here point at each other to show height.
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The speed limit ahead is 3.9
Speeds in Ontario are posted in km/h, and speed limits ride on their own regulatory sign. The letter m stands for metres, a measurement of height, not speed.
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The lane is 3.9 metres wide
The arrows on this sign point up and down, so they measure height, not width. A narrowing road gets its own warning sign showing the pavement pinching in.
Quick way to remember
The number with "m" is a measurement of height.
Based on the official Ontario MTO Driver's Handbook.
Reading it once is not enough
Drill this question in a scored round and find out what else you are shaky on.
Practise Road Signs: Warnings
