A General Guide
Speed Cushions which have been used elsewhere in Europe for a number of years were introduced in this country during the early 1990's to provide an alternative speed control measure which avoids some of the problems associated with road humps.
Speed Cushions are a raised section of the carriageway which smaller vehicles have to drive over but can be straddled by larger vehicles such as buses and fire engines. In a similar way to road humps, cushions are installed at regular intervals along the carriageway to ensure that low speeds are maintained.
There are three main types of speed cushion layout:
- A series of single cushions combined with carriageway narrowings or hatch markings.
- Pairs of cushions (allowing two way working, suitable for higher flow roads).
- Groups of cushions three abreast (also allowing two way working), used on wider carriageways avoiding the need to use road narrowing measures.
Speed Cushions offer a number of benefits as a speed reduction measure:
- They can contribute to the reduction in the number and severity of accidents.
- They can reduce the volume of through traffic.
- They do not adversely affect buses and emergency vehicles in the same way as road humps.
- Cyclists and motorcyclists can pass between the cushions.
However, there are a number of inherent disadvantages:
- Overall, they are less effective as a speed reducing measure than road humps, particularly where lorry flows are significant.
- It maybe necessary to prohibit parking on approaches to the cushions.
- They are generally difficult and expensive to construct.
- They can generate noise and vibration although it is less of a problem than with road humps.
- They can be considered visually intrusive due to the use of colours that contrast with the normal road colour.
- They cannot be used at pedestrian crossing places because they can constitute a trip hazard.
- They generate additional highway maintenance costs.
- They can only be used on roads subject to a speed limit of 30mph or lower.
Although the introduction of Speed Cushions does not require the making of a Traffic Regulation Order, a statutory process needs to be followed which involves consultation and public advertisement.