20mph speed limits and zones
Speed limits as low as 20mph should normally be introduced with extensive traffic calming measures (e.g. speed tables, and speed cushions) to ensure that speeds are in compliance with the limit, or where speeds are already low.
When considering the appropriate speed limit, other factors must be assessed as installing the wrong speed limit on a road will mean it won’t work properly. The speed limit must be appropriate, taking into account all the road’s characteristics and the surrounding environment, such as whether the locality is a built up area, near a school or a town centre.
20mph zones have generally been considered in residential areas to keep speeds low.
The costing could be dependant on locality and for example a traffic calmed area the cost would be in excess of £100,000.
An advisory 20mph limit outside a school also includes a sign and flashing lights. These advisory limits are highlighted at school start and finish times. A pair of signs and lights would cost approximately £10,000.
All costs stated are for guidance only.
Figures provided are estimates and are reviewed annually, with all costs subject to a site survey assessment.
For further guidance see the Department for Transport: Local Transport Note on Traffic calming