Speed humps and traffic calming
The Council receives many requests from residents for these to be introduced in their roads to reduce speeds and improve safety.
There is usually opposition from the Police, Fire Brigade, Ambulance Service and Bus Companies to the use of speed control humps. The Emergency Services object because humps increase their attendance times for emergency calls, and thus risk the lives and property of the people. The Ambulance Service and Bus Companies object because of the discomfort and possible injury that may be caused to their passengers and the increased wear and tear on vehicles, particularly buses going over speed tables every day.
There are regulations governing the layout of speed control humps. There must be a form of "slowing feature" - usually formed by a change of priority (traffic entering the system has to turn sharp left or right into the road, or has to "give way". Sometimes mini roundabouts are used at the start of a system of humps.
The shape of speed control humps are strictly regulated. They must be between 50mm and 100mm high, at least 2.75m long and extend over the full width of the road, except for a drainage channel at either end. They may have either flat tops or round tops. Many local authorities have adopted the 75mm high hump as a standard. This is because it has been found to reduce traffic to around 22 mph. The 100 mm high humps reduce speeds to 17 mph on the hump but speeds rise to 35 mph between the humps, causing excessive acceleration, braking and increased pollution. Flat topped humps can be of any length and are often known as "speed tables". They are sometimes used to reduce the impact on long wheel base vehicles such as buses.
Speed control humps can lead to complaints about increased noise and sometimes increased vibration from traffic. They have however been proved to reduce traffic speed and they have been installed in many locations.
Pillow or Cushion Humps
These are a form of speed control hump which are wide enough to allow a wide wheelbase vehicle to pass unhindered. Buses or a fire engines are not affected by them, whereas a smaller wheelbase vehicle, such as a car, would have to have at least one set of wheels on the hump. Thus cars are slowed, whereas other traffic is generally unaffected. These are intended to overcome the objections of the Emergency Services and Bus Companies.
They make possible speed reduction measures in roads that would otherwise not have them introduced.
For information or to complain about speed humps, please contact us using the details on the right.
Other traffic calming methods
Chicanes and Throttles
Chicanes and throttles are intended to reduce traffic speed by reducing the available carriageway width throughout a short length.
Chicanes introduce a physical deflection into the vehicles' horizontal path, thereby further reducing the vehicle speed.
Throttles narrow the road, frequently to provide a safe crossing point for pedestrians, sometimes in conjunction with a speed table.
Kerb Build Outs
At some road junctions visibility is often reduced because of the shape of the road or because of parked cars. Building out the kerb into the carriageway can help solve this problem. It provides protection for motorists emerging from a side road as they can safely pull further out to see, and be seen. Pedestrians are similarly protected, have more space to stand and can also see and be seen better. Cars are forced to park further from a junction or crossing point.
Width Restrictions
Width restriction are a self enforcing means of restricting access for large vehicles. Posts or bollards are placed in the road about 2.1 metres (7 feet) apart, such that vehicles wider than this cannot pass between them. There must be an alternative route available for large vehicles such as refuse collection vehicles and this sometimes limits their application in residential areas.
Sometimes a gate is provided for use of fire engines and other emergency vehicles. The gate is kept locked but emergency vehicles carry keys.
Many residents mistakenly ask for width restrictions to be introduced as a means of slowing down traffic. Width restrictions do not, and are not intended to, reduce traffic speed.
One Way Streets, Banned Turns and No Entry
These help control traffic movements, without completely restricting access. They can stop commuter "rat-runs" which occur.
One-way working may be for the whole length of a street, or in a short length at one end - a one-way plug.
A suitable alternative route must be identified and available for traffic travelling in the opposite direction to the one-way street, or for traffic needing to turn in the direction of the ban. This alternative would not normally be via a residential road.
One-way streets often lead to an increase in traffic speed. Short lengths are difficult to enforce if drivers are irresponsible and determined enough to drive against the one-way. This is dangerous and illegal.
Some residents find one-way streets and banned movements inconvenient as they may result in reduced levels access to their homes.
Road Closures
These are an effective, self-enforcing, means of stopping all through traffic movements. Roads are usually closed by a barrier with an emergency access gate for Police, Fire and Ambulance vehicles.
Near to a road closure, it is necessary to make provision, on either side, for large vehicles to turn round. That is why it is not used in many residential areas. It may also be inconvenient to some residents as Road Closures limit access.
Standard Roundabouts
Standard roundabouts are intended to assist at a junction where there is a heavy right turning movement. They work best where traffic flows on each arm are reasonably well balanced and they allow traffic to flow comparatively freely.
Mini Roundabouts
Mini roundabouts are introduced both as a means of reducing accidents, by slowing traffic, and to assist right turning movements. Their advantage over full size roundabouts is that they can often be accommodated within the existing road space, without expensive road widening.
As at a full size roundabout, the rule at a mini roundabout is "give way to traffic from the right".
Page updated: 27 Oct 2011
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