Speed bumps turn 40! ROB HULL asks: are the traffic-slowing measures still fit for purpose?

The mobile phone. Super Mario Bros. McDonald’s chicken McNuggets. And me. What do all these things have in common? 

They all turned 40 this year.

And there’s a particular staple of drivers’ daily lives that is also celebrating its 40th anniversary in 2023… the speed bump.

While they originate back to early 1900s America, the first installed on a British road as a traffic calming measure didn’t arrive until 1983. Today, there are believed to be over 42,000 of them across the UK’s road network. 

But are they still fit for purpose? With reports of expensive damage caused to vehicles and suggestions that they increase air pollution in densely-populated areas, could their time soon be up?

Do you know of a particularly big or poor quality speed bump near you? If so, send us a photo of it as we hunt down Britain’s most-hated ‘sleeping policeman’ – editor@thisismoney.co.uk

Happy 40th birthday to the speed bump: The first iteration of this traffic-calming measure was installed on a UK road in 1983. Four decades on, is it still fit for purpose today?

A brief history of speed bumps

The first known speed bump added to a road reportedly appeared on 22 April 1906 in Chatham, New Jersey. 

It was introduced in a residential area to reduce the speed of motor vehicles that had reached the capability of cruising at an average of 30mph.

The first rubber speed bump didn’t follow until almost 50 years later when in 1953 Nobel Prize-winning physicist Arthur Holly Compton invented the ‘Holly Hump’. 

The first speed bump was installed in Europe in 1970 in Delft in the Netherlands, though it took another 13 years before they came to Britain as part of the original Highways (Road Hump) Regulations in 1983.

This allowed round-top humps 3.7 metres in length with heights of up to 100mm to be installed on roads in England and Wales with a speed limit of 30mph or less.

As more appeared on roads in the eighties, drivers began to refer to them as ‘sleeping policemen’ – this is due to their ability to remind motorist they need to be aware of their speed. 

Traffic signs warning of speed humps ahead are only compulsory on roads where the speed limit exceeds 20mph

How big are speed bumps and where can they be installed? 

The latest iteration of the Highways (Road humps) Regulations 1999 dictates that all speed bumps must be at least 900mm in length and with a height between 25mm and 100mm at its tallest point.

No vertical face or material forming the speed hump may exceed 6mm and the gradient of a speed bump must be no more than 1:10.

They also must always be placed at a right angle to an imaginary line which runs down the centre of a road and can only be installed on roads where the speed limit is lower than 30mph.

They cannot be fitted within 30 meters of a Zebra, Pelican and Puffin Pedestrian Crossings and within 20 meters of a railway track at a crossing if the speed limit is greater than 20mph.

They also cannot be placed within 25 metres of a bridge or tunnel where the structure crosses the path of a highway.

If the speed limit is over 20mph, speed bumps cannot be used in areas where there is no street lighting. In fact, there must be at least three street lamps distanced no further than 38 metres apart to the next one along to ensure drivers can see the obstruction ahead.

This is because traffic signs are only compulsory on roads where the speed limit exceeds 20mph. 

The latest iteration of the Highways (Road humps) Regulations 1999 dictates that all speed bumps must be at least 900mm in length and with a height between 25mm and 100mm at its tallest point. No vertical face or material forming the speed hump may exceed 6mm and the gradient of a speed bump must be no more than 1:10

How many speed bumps are there on Britain’s roads?

Council data shared with car maker Citroen in 2019 suggested there are more than 42,000 individual speed bumps on more than 14,000 roads in Britain, stretching across an estimated 2,000 miles of streets. 

Unsurprisingly, London Borough councils have the highest percentage of speed bumps per miles of road.

Eight councils in the capital account for the top 10 with the most speed humps.

Topping the list was Newham Council, which said the entirety of  its 124 miles of roads has speed bumps installed on them.

It was followed by Southwark and Hackney, with 148 miles (71 per cent of all routes) and 104 miles (69 per cent) of speed-bumped roads in their jurisdictions respectively. 

Outside of London, Norwich City Council topped the league table with the traffic calming measures installed on 17 per cent of its roads ahead of Portsmouth City Council (13 per cent) and Bury Metropolitan Borough Council (12 per cent). 

This map shows which locations have the highest volume of speed humps per mile of road, according to a report by Citroen in 2019. The data is split into London Boroughs (which have the most in general) and councils outside of the capital

Do speed bumps reduce road casualties? 

Road safety experts say traffic calming measures like speed bumps are one of the key reasons why deaths on UK roads are lower than almost every other country. 

That said, they are a regular source of complaint for motorists, especially those who suffer vehicle damage from driving over them.  

Ambulance drivers and the fire brigade have also hit out at them in the past. 

Meanwhile, poorly installed bumps have also been blamed for speeding up the deterioration of road surfaces and an increase in vehicle emissions due to constant braking and accelerating.

Back in 2019, Steve Gooding, director of the RAC Foundation, told us that other forms of traffic calming – such as chicanes – should be considered ahead of speed bumps. 

He told This is Money: ‘This proliferation of speed humps, speed cushions, speed ramp, speed tables, sleeping policemen – call them what you will – are put in place with the best of intentions. 

‘However, they risk giving drivers, bikers and cyclists extremely uncomfortable rides especially if they fall into disrepair. 

‘Road engineering offers other traffic calming solutions and these should be given equal consideration when the planners are at the drawing board.’

If drivers sustain damage to their vehicle when going over a speed hump they can claim for compensation if the bump is bigger than rules allow

Do speed bumps cause damage to vehicles and how much will it cost to repair on average? 

A 2018 investigation by Confused.com found that 22 per cent of motorists had experienced some form of car damage caused by the humps in the road.

The average cost to fix a car that’s sustained damage when driving over a speed bump is £144, according to the comparison site’s research.

Many drivers were found to have demanded to be compensated for repair costs, with local councils having to pay out £35,000 in reimbursements between 2015 and 2017 – 45 per cent of claims being made in London.

However, this is only the case when a speed hump is found to exceed legal heights listed above.  

The comparison website said the most common form of damage caused by speed bumps is tyre related.

A poll by Confused.com in 2018 found that 22% of 2,000 motorists polled had caused damage to their vehicles when going over speed bumps

Do speed bumps increase air pollution?

Any traffic calming measures that require drivers to slow down and speed up frequently will ultimately increase the emissions produced by vehicles.

However, the argument is that the small increase in pollution is offset by their impact on road safety. 

In 2017, then Environment Secretary Michael Gove suggested councils should consider removing them entirely to ‘optimise traffic flow’ to bring down dangerous levels of nitrogen dioxide.

He said that ‘improving road layouts and junctions to optimise traffic flow, for example by considering removal of road humps’ should be considered ahead of the introduction of clean air zones in Britain and a ban on sales of new petrol and diesel cars – which have subsequently already launched across the country and been proposed (though delayed recently) respectively.

While there have been suggestions that speed bump may increase vehicle emissions in residential areas, experts believe this fails to offset the safety benefits associated with their ability to slow down traffic

Transport Research Laboratory technical manager, Tim Barlow, told Transport Network in 2017 that traffic calming measures ‘can cause an increase in harmful tail pipe emissions and CO2’, with speed humps ‘tending to have the largest increases’.

However, he said their primary job is to reduce speed to save lives in residential areas, which he claimed ‘don’t normally have air quality problems’. 

For this reason, he believes speed humps and bumps do not significantly contribute to the total amount of harmful vehicle pollutants that are created.

In a joint letter issued to Mr Gove from the Campaign for Better Transport, Living Streets and Cycling UK said: ‘Local authorities should be able to demonstrate that any proposed alternative to speed humps is at least as effective in controlling speeds, preventing injuries and fatalities and improving public health for people of all ages and abilities, including children and other non-drivers.’