Minimum speed sign

What it means

This sets a minimum speed. Traffic must not go slower than the number shown, unless that would be impracticable or unsafe.

It's easy to mistake for a speed limit. The difference is the colour: a red ring sets a maximum, while a blue circle gives a positive instruction, here a minimum speed.

A matching sign with a red diagonal line across it marks the end of the minimum speed requirement.

What the symbol shows

A blue circle gives an instruction, so a number on blue is a speed you must keep to as a minimum, not a limit you must stay under.

Memory tip: Red ring sets the ceiling; a blue circle sets the floor.

Rules to know

• The sign shows the minimum speed permitted, in miles per hour, unless it is impracticable or unsafe to comply.

  Know Your Traffic Signs, p. 23

• A blue circle generally gives a positive (mandatory) instruction.

  Know Your Traffic Signs, p. 16

Spot the difference

Minimum speed vs Maximum speed limit

The key difference: A red ring sets the most you may do. A blue circle sets the least you must do, unless that's impracticable or unsafe.

Differences between the Minimum speed and Maximum speed limit signs

	Minimum speed	Maximum speed limit
Looks like	White number on a blue circle	Black number in a red ring
Means	Minimum speed	Maximum speed

Know Your Traffic Signs, Speed limit signs, pp. 21 and 23

Common mistakes

• Mistake: Reading it as a 30 mph speed limit.

  Instead: A blue circle with a number is a minimum speed. Speed limits have a red ring.

• Mistake: Thinking you must keep to the minimum whatever happens.

  Instead: You don't have to if it's impracticable or unsafe, for example in heavy traffic.

Test yourself

Recalling the answer helps it stick. Pick an answer to see how you did.

Question 1 of 2

What does this sign mean?

• AYou must not go slower than the speed shown, unless it's impracticable or unsafe.
• BNo vehicles may use the road, except pedal cycles being pushed by hand.
• CYou must turn left at the junction ahead.
• DYou must not go faster than the number shown, in mph.

Full road sign quizzes are coming soon. See what's planned