Approaching a narrow village bridge, you see a plain red circular sign with a white background showing the number '7.5t' in black. What does this sign mean for the driver of a car weighing well under 7.5 tonnes?
- The sign applies to every vehicle regardless of weight; all traffic must find an alternative route
- The sign has no effect on the car, since the restriction only applies to vehicles at or above the weight shown; the car may proceed
- The car must reduce speed to 7.5 mph while crossing the bridge
- The number refers to the maximum number of vehicles allowed on the bridge at once, not a weight
Why B? And why not the others?
Correct answer: B. The sign has no effect on the car, since the restriction only applies to vehicles at or above the weight shown; the car may proceed
A red circular sign showing a tonnage figure is a maximum-gross-weight prohibition: it bans any vehicle whose actual weight is at or above the figure shown from using that stretch of road or structure, typically to protect a weak bridge or narrow lane from heavy vehicles, so a car weighing well under the stated figure is not restricted at all and may proceed normally. Claiming the sign applies to every vehicle regardless of weight is wrong because the whole point of a numbered weight-limit circle is to draw a threshold, exempting anything below it, unlike an unqualified prohibition sign carrying no number. Reading the figure as a speed limit confuses this sign with a completely different circular sign showing a number followed by mph; a weight-limit sign's units are always a mass, such as tonnes, never a speed. Treating the number as a vehicle count is also incorrect, since UK weight-restriction signs regulate the mass of an individual vehicle crossing, not how many vehicles may be present at once, which UK traffic signs do not regulate at all.
Source: The Highway Code: Traffic signs — signs giving orders (GOV.UK), maximum gross weight sign