Log in or register
My AA Account

Sign in to see your cover and request assistance online

Log in

Don’t have a My AA account?

You’ll need your policy or membership number

Create an account

Your Finances

Loans | Savings | Credit Cards

Your Driving Lessons

Book a lesson

Speed limits

Laws for major and minor roads

The speed you can drive is limited by the type of road being used and the type of vehicle being driven. If two or more speed limits apply, then the lower or lowest limit must be observed.

Speed limits do not apply to a vehicle being used for fire brigade, ambulance or police purposes if keeping to the limit would hinder its efficiency while responding to an emergency.

No other vehicle is exempt.

Speed limits on roads

A single carriageway is where traffic flows in either direction on an undivided road (often with a centre white line marking). The road may have one or more lanes in either direction. It may be subject to any speed limit up to the national speed limit.

A dual carriageway is a road consisting of two parts, separated by a central reservation, each part of the road being used by traffic travelling in one direction only. It may be subject to any speed limit up to the national speed limit.

Mandatory speed limit signs

Mandatory speed limit signs are circular. The sign for a maximum speed limit shows black numerals on a white background with a red border.

On a Class A or Class B road in Scotland with appropriate street lighting, a 30mph sign is required to indicate the point at which it becomes a restricted road.

Minimum speed limit sign

This sign indicates a minimum speed limit which is mandatory. At the start, the sign has white numerals on a blue background and at the finish there is a similar sign crossed through with a red diagonal line.

National speed limit sign

This sign indicates that the national speed limit applies:

60mph on a single carriageway
70mph on a dual carriageway

You would expect to see this sign at the point where a lower limit ends. Remember that a lower limit than the national speed limit might still apply to you because of your vehicle or because you are drawing a trailer.

The maximum speed limit on motorways is 70mph unless signs indicate otherwise. On some motorways, variable speed limits operate. The signs indicating these are mandatory speed limit signs but produced by lamps. When not in use they show a blank grey or black face.

Local limits

Local authorities can set their own limits to address specific local needs. (20mph zones are increasingly being applied in built up areas or around a school.) Signs must be clear.

20 mph limits

According to government guidelines, 20mph limits can be introduced where there are significant numbers of vulnerable road users. Successful limits and zones should be self-enforcing through site conditions such as signing or traffic calming leading to a mean traffic speed which is compliant. There should be no expectation on the police to provide additional enforcement beyond routine activity.

According to revised ACPO guidelines (October 2013) , enforcement will be considered in all clearly posted limits, given other priorities, and this will be by:

  1. Targeted enforcement where there is deliberate offending/disregarding and the limits are clear
  2. Where limits are not clear (they don't feel like/look like the limit or are on inappropriate roads), they will not be routinely enforced but may be targeted where there is intelligence of obvious deliberate disregard.

In November 2013 the National Driver Offender Retraining Scheme (NDORS) introduced a speed awareness course specifically tailored to speeding offences in 20mph limits where, at the discretion of the police, offenders who are either "mistaken or simply unaware of the limit" would benefit from education. Speeding in a properly marked or engineered limit or zone may not be suitable for a course.



Speeding offences are enforced by the police using fixed, mobile or average speed cameras and are generally dealt with using the Fixed Penalty Notice system.

The minimum penalty for speeding is generally a £100 fine and three points on your licence though in some areas at the discretion of the police and for more minor speeding offences only you might be given the opportunity to attend a speed awareness course.

You will not be able to attend a course if you have already done so anywhere else in the country within 3 years.

The course will cost you more than the original fixed penalty but if you complete it you will not have three penalty points endorsed on your licence.

ACPO guidelines for speed limit enforcement

These guidelines do not replace police officer discretion.

Limit Fixed penalty
when course not
awareness course
course to:
Summons in
all other
cases above:
20mph 24mph 24mph 31mph 35mph
30mph 35mph 35mph 42mph 50mph
40mph 46mph 46mph 53mph 66mph
50mph 57mph 57mph 64mph 76mph
60mph 68mph 68mph 75mph 86mph
70mph 79mph 79mph 86mph 96mph


Mandatory signs

Mandatory signs must, with certain exceptions, be placed on both sides of the carriageway at the point where a speed limit begins.

(Page updated 14 October 2013)