The majority of the road network is subject to national speed limits. These national limits apply unless a Traffic Regulation Order is made to alter the limit on a length of road. Speed limit terminal signs and repeater signs will be erected where such an Order has been made.

The default national speed limits which apply, unless signs indicate otherwise, are 30 mph in a street lit area; 60 mph on a single carriageway road without street lighting; and 70 mph on a dual carriageway road without street lighting. (Please note that different speed limits apply for certain classes of vehicle such as buses, heavy goods vehicles and cars towing caravans).

Terminal signs are provided wherever there is a change from one speed limit to another.

Changes to existing speed limits are considered in line with national guidelines

Where a change to an existing speed limit is being considered, this is carried out using central government guidelines. The purpose of these national guidelines is to ensure that there is consistency between different local authority areas for the travelling motorist.

The factors that are taken into account when setting a speed limit include existing traffic speeds, accident history and the character of the road under consideration. Any changes to speed limits must be made with full agreement of the Police as they are responsible for the enforcement of such limits.