How high is a speed bump? UK heights and the rules

November 9, 2026

In the UK, a road hump must be between 25mm and 100mm high. That range is set by The Highways (Road Humps) Regulations 1999. In practice most installations sit between 50mm and 75mm, because that is the band that slows traffic reliably without grounding a low car or jarring a delivery van.

The short answer

Minimum height: 25mm
Maximum height: 100mm
Most common in car parks and on private roads: 50mm to 75mm

Those figures apply to road humps on the public highway. On private land, a car park or a business park, you are not bound by the regulations in the same way, but they remain the sensible guide: a hump outside that range is either ignored by drivers or damages vehicles.

Choosing between 50mm and 70mm

The height you want depends on the speed you are trying to enforce and on what drives over it.

50mm suits car parks, retail sites and anywhere with a 10mph limit. It is firm enough to be felt but gentle enough for frequent traffic, and it is the safer choice where vans and minibuses pass all day.
70mm suits access roads, industrial estates and school approaches where you want traffic at walking pace. It is more assertive and drivers slow further for it.

If emergency vehicles or buses use the route, take advice before installing anything above 50mm. Ambulances in particular are affected by hump height, and speed cushions are often the better answer because their width lets a wide axle straddle them.

Length and spacing matter as much as height

A tall hump on its own does not produce a slow road. Spacing does. Humps set 20 to 40 metres apart keep speeds down along the whole stretch, because a driver never gets the run-up to accelerate between them. Humps 100 metres apart produce a sequence of braking and accelerating, which is noisier and no safer.

Speed bumps, humps and cushions

Speed bump: short, usually under a metre front to back. Aggressive at low speed, common in car parks.
Speed hump: longer and rounded, often the full width of the road. Smoother, used on residential roads.
Speed cushion: a raised pad narrower than the lane, so cars straddle one wheel over it while buses and fire appliances pass with the axle either side.

Installing them

Modular rubber bumps bolt to concrete or tarmac and can be lifted and moved if the site layout changes, which matters on a car park that gets re-lined. End caps matter more than people expect: an unterminated hump is a trip hazard and gets clipped by wheels.

We supply traffic calming in both 50mm and 70mm heights, with end caps and fixings, priced including delivery. If you are not sure which height suits your site, tell us what uses the road and we will advise before you order.