Blog: Don't get the hump with the bumps - Speed bumps explained

Blog: Don't get the hump with the bumps - Speed bumps explained

Different types of speed bump

Speed bump or speed hump?

Speed bumps – These are the smaller, usually plastic or rubber bumps that stretch across the road. They can be up to 100mm high, and are there so a car has to slow to around 5mph to drive over them without damage. They are usually found in car parks and other areas with a 5mph limit.

Speed humps/round top – These are the “sleeping policemen” - concrete humps that span the whole width of the road. You usually find these in residential areas, but not if the road is used as a bus route.

Sinusoidal – These are pretty much the same as round top humps except that the initial incline is a little less steep.

Speed cushions – These are the “square” humps that are in 2’s or 3’s over the width road. You can go a little quicker over these, and are usually found in 30mph zones.

Speed tables/flat top/raised junction – You usually see these as zebra crossings. They are an elevated section of road, with a flattened top. Or, in the case of a raised junction, the whole junction is elevated. Lorries, buses and other heavy vehicles can get over speed tables easier than traditional speed humps.

‘H’ road humps/’S’ road humps – These road humps try and make it easy to manoeuvre for both cars and bigger vehicles like buses or lorries. The outer edges – for wide vehicles – have a shallower incline than the slope in the middle – for cars.

Surprise surprise, one is shaped like an S and one is shaped like a H.

What can happen when you go too fast

In essence, you’ll damage your car.

Since speed bumps, humps and tables are there to make you slow down, you should probably do just that, otherwise you may cause damage to the suspension system and steering system.

There’s also these factors to consider with just general use:

  • Emergency vehicles may be hindered from getting to their destination quickly
  • Motorcycles and bicycles may be de-stabilised
  • Heavier vehicles can cause tremors when going over them that can be felt in surrounding buildings and may damage the road itself

Other traffic calming measures

Speed bumps certainly work, but are they really the perfect solution to slow cars down? And with the effects of extra pollution and noise due to breaking and revving to get you back up to speed, are they worth the hassle?

Well, what else is there to calm traffic?

Chicanes – These are sections of road which are artificially made into a one-way curve in order to slow approaching traffic and let others pass.

Not like the ones you see in F1.

Rumble devices – These are small “bumps” (nothing like the above) in the road to warn you of an approaching hazard and make you aware of your speed. You may also encounter them when you accidentally drift near the hard shoulder or central reservation on a motorway.

Speed cameras – We all know what these are. If you speed, you can expect a flash and a fine through the door. These are traffic calming measures activated by the vehicle, like some electronic traffic signs such as speed limits outside of residential areas that remind you if you’re going a little too quickly.

Mini roundabouts – Not only does this slow traffic down, but is also good for an otherwise difficult junction.  These can sometimes be called roundels, which is pretty much a mini roundabout painted on the road.

For the lowdown on all traffic calming measures, check out the government website or check out this report.


New types of speed bump

There are new speed bumps being trialled over the world in an effort to minimise some of the negative effects that “regular” speed bumps have on the environment.


In essence, the Actibump is the opposite of your conventional speed bump. Instead of having to go over an obstruction in the road, drivers need to slow to allow time for a piece of the road to essentially “raise up” so they don’t hit a man-made pothole.


Smart speedbump

This nifty piece of technology uses a non-Newtonian liquid in a plastic cover. The properties of a non-Newtonian liquid mean that when they are subject to a sudden force, the liquid acts as a solid. But, if it is subject to a slow force, it acts more like a liquid.

Kind of like custard.

So, how would that work in a speed bump?

Well, the slower you go over it, the smoother it would be. Therefore, there would be less resistance when you go through it.

But although these new inventions tackle some of the problems that come with speed humps, not everything is covered. e.g. – the emergency vehicle conundrum.

The future

There has been a lot of discussion whether to remove speed bumps entirely from the road – some as recently as last year.

With a strong focus on pollution and emissions from motors (particularly diesel), an article from The Telegraph suggests that speed bumps and other traffic calming measures actually increase pollution due to constantly slowing down and speeding up, as well as decreasing fuel efficiency.

So what does this mean for traffic calming measures in general?

With councils under pressure to improve the flow of traffic and pollution levels in town, there may be no choice but to stop traditional traffic calming measures altogether.

Of course, this may not happen for a little while – in fact we don’t know if and when that’ll happen. But with the government planning on being fossil-fuel-vehicle-free by 2040, you have to ask whether there’s much point of removing the measures if there will be non-polluting cars on our roads in the future.

  • On: 31 July 2018
  • By: CarShop

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