Traffic calming

Traffic-calming measures are used to encourage people to drive at a lower speed than they might otherwise do. They’re used in particularly sensitive areas where it’s considered that a reduction in speed would benefit the immediate community.

Various features can be provided to slow down traffic, such as

• road humps
• road narrowings, central islands and chicanes
• mini-roundabouts.

20 mph zones

Some traffic-calmed areas are indicated only by a 20 mph (32 km/h) speedlimit sign.

This speed-limit sign, in addition to advising the maximum speed, indicates that there may be traffic-calming features within the signed zone; these may not be individually signed.

You should drive at a steady speed within the speed limit, and avoid frequent acceleration and deceleration within these areas.

Road humps

These may be round- or flat-topped humps laid across the carriageway. They may be used on roads where there’s a speed limit of 30 mph (48 km/h) or less.

In some areas the humps are in the form of ‘cushions’, which cover only part of the lane and are designed so that larger vehicles, especially buses, can straddle them.

If road humps or cushions are provided outside 20 mph (32 km/h) zones, there will normally be

• warning signs at the beginning of the section of road where the hump or series of humps is installed
• triangle and edge line markings at each hump.

Road narrowings

Roads may be narrowed by the use of ‘build-outs’ on one or both sides of the road. If these are provided outside 20 mph (32 km/h) zones, there will normally be

• warning signs indicating on which side of the road the narrowing occurs
• ‘give way’ road markings on one side of the road, accompanied by signs advising priority for oncoming vehicles.

If these are on your side of the road, you MUST always give way to drivers approaching from the other direction.

If priority isn’t given in either direction, then all drivers should ensure that they can pass through the narrowing without endangering vehicles approaching from the other direction. You shouldn’t accelerate as you approach the narrowing, but be prepared to slow down or give way to approaching traffic.

Hold back and allow cyclists and motorcyclists room to pass through; don’t try to squeeze through at the same time.

Mini-roundabouts

Mini-roundabouts are often used as part of traffic-calming schemes to break up a long road into shorter sections and allow traffic to join from minor roads.

Methods of dealing with mini-roundabouts are given in section 8.

Psychological traffic calming

Shared spaces are areas where road furniture such as kerbs, traffic lights, signs, white lines and other road markings are removed to create ‘naked roads’. The theory is that removing the sense of security provided by road furniture causes the driver to exercise more caution. This scheme is under review and the Department for Transport has advised local authorities to pause the development of shared space schemes.