Introduction to traffic calming
Well-designed traffic calming measures can reduce traffic speed, but it is important to avoid any issues for cyclists and disabled people.
New residential streets should be designed with low traffic speeds in mind. High-quality street design can create a sense of place and add visual interest to a streetscape, while slowing down motorised vehicles. Examples of good quality traffic calming include adding greenery and architectural detailing.
Traffic calming on existing streets
Traffic calming measures may be needed on existing streets that are poorly designed and do not prevent speeding to improve the safety of people walking, wheeling and cycling. The measures need to be well-designed, and should be fitted sensitively into the street scene, especially in historic and conservation areas.
Measures should be effective without causing issues for cyclists and accessible for disabled people and people on tandems and tricycles.
Traffic calming examples
Some traffic calming measures are best avoided or should only be used sparingly and/or in a suitable location. Some examples of traffic-calming measures are set out below:
Road narrowing and horizontal deflection
Road narrowing can reduce speeds, but minimum widths set out in Cycle Infrastructure Design (LTN 1/20) need to be adhered to. Section 7.2 sets out recommended widths for streets, including minimum lane widths.
The ATE route check identifies a critical width of 3.25m and 3.9m. Kerb build outs may be used if designed correctly, and parking bays and greenery can be used to narrow a road.
Horizontal deflection means using street design to prevent motorists from driving in a straight path. This is an effective traffic calming measure. However, blind bends should be avoided.
Speed humps, tables and cushions
Speed humps, speed tables or speed cushions should be in line with Cycle Infrastructure Design (LTN 1/20) figure 7.8. Speed cushions should be avoided as it can force a cyclist into changing their position on the road, which may conflict with motorised traffic.
Any speed hump should not exceed an angle 12.5% as this would risk destabilising and unseating a cyclist.
Surface treatments and rumble strips
Surface treatments, such as block paving can reduce speeds but may cause levels of discomfort, especially for disabled cyclists, older and younger cyclists. They should therefore be used sparingly.
Rumble strips can reduce speeds but may also cause discomfort as with surface treatments so should be used sparingly.
Tight side road kerbs reduce speeds and increase safety for pedestrians and cyclists at side roads.
The absence of line markings can reduce speeds.
