The Council receives many requests from residents for these to be introduced in their roads to reduce speeds and improve safety.
There are regulations governing the layout of speed control humps. Speed control humps can only be installed as part of a series of speed reducing features. In other words we cannot just put in one or two 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.
In general the Council will not install traffic calming measures in just one road. This is because traffic calming one road tends simply to move the problems into adjacent roads. The Council has a well-established traffic calming policy, based on area-wide studies. This has the advantage that we are able to introduce 20mph zones which actually work. This also makes it less likely that we will move rat-running problems from one street to another. We adopted this method in 2001 and divided the borough into areas, using major roads or railways as boundaries. These schemes are funded by money we bid for from Transport for London and we generally can take forward one or two areas a year.
A number of roads in the borough form the Emergency Services Priority Route Network (ESPRN). The Council does not use full width speed control humps on these roads. This is because humps can jeopardise emergency service response times.
The Council does make special provision for bus routes and emergency service routes. On these roads we use the smaller square ‘speed cushions’. These do reduce vehicle speeds, though not as effectively as full width humps, and can be straddled by wide axled vehicles (buses, ambulances fire engines etc).
The shape of speed control humps is 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 22mph. The 100mm high humps reduce speeds to 17mph on the hump but speeds rise to 35mph 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.
FAQ
I feel that traffic calming measures are needed in my road. how can I bring this to the attention of the council?
Speeding on roads in residential areas is one of the most common complaints that we receive in the traffic office. Indeed, requests from concerned residents, to provide 'traffic calming' on our road network, are received regularly from all over the borough.
Lewisham’s road safety policy was radically revised in the summer of 2001 when the Council’s Executive Committee approved an area-based approach for future traffic management issues.
The borough has been divided into a number of discreet areas, each of which is bounded by well-established through routes. All of these areas have been assessed and prioritised according to their current need for traffic calming. Those most in need are being investigated and treated now and the rest will follow when funding is approved.
This approach has a number of advantages:
- it provides an opportunity for local communities to highlight and discuss what they consider to be the most important traffic-related problems. Our engineers can then effectively address local concerns
- it avoids the displacement of traffic problems onto neighbouring streets
- area-wide measures such as 20mph zones can be introduced.
How are the areas prioritised?
The priority list is based on the accident data.
Can the council put a speed camera in my road?
Traffic speeds can be monitored through the use of speed cameras. The London Safety Camera Partnership (working for Transport for London) is responsible for the use of speed cameras in London. Their criteria for speed camera enforcement is that they are only used at locations with the highest numbers of speed-related accidents.
Transport for London is responsible for the installation of the cameras and the resulting penalty charges/prosecution are handled by the Police.
How does the council enforce the speed limit in 20mph zones?
Under current legislation the Council has no powers to enforce against moving traffic offences. Enforcement against offences such as speeding and contravention of banned turns is a matter for the Police. The Police have however stated that they could not make any commitment to carry out routine enforcement of 20mph zones. This is because there is in law no fixed penalty (as there is for other speed limits) that can be issued to drivers breaking the speed limit in a 20mph zone. The Police would be forced to arrest, charge and prosecute offenders, and this would take up a disproportionate amount of Police time and resources.
Under Government guidance, when a 20mph zone is introduced it must be supported by physical measures (humps etc). The recommendations make it clear that the aim should be to ensure that vehicle speeds are maintained at or below 20mph by the use of physical measures.
In an urban environment however, allowances often have to be made for access by emergency service vehicles and buses. It is not always possible to ‘engineer out’ all irresponsible driver behaviour.
However, whilst the measures in certain locations may not reduce vehicle speeds to 20mph or below, the initial evidence indicates that 20mph zones have a beneficial effect in reducing speeds generally. There is also a general environmental improvement and a significant safety benefit in the areas treated.
Does Lewisham plan to introduce any Home Zones?
The Council has an agreed policy for area traffic calming, and has approved a prioritised approach for treating areas based on the number of personal injury accidents. Incorporated into this approach are both the Safe Routes to Schools and Home Zone concepts.
Home Zones are very expensive for the number of roads treated. Our approach therefore is to use the area traffic calming as a base to deal with the majority of problems in an area, but to design in such a way that it is upgradeable to a Home Zone at a later date as and when money becomes available.
There have been lots of cars damaged in my road. Can the Council put in speed humps?
When the Council assesses an area to determine its need for traffic calming the criteria used is the number of personal injury accidents. However we do not take into account accidents where only vehicles are damaged. This is because there are no reliable sources of information about 'damage only accidents' because they do not have to be reported to the Police. We are also aware that there is under reporting of personal injury accidents although drivers are legally required to report all injury accidents.
It would be impossible to take into account unreported personal injury accidents for the very reason that we do not know how many there are or their circumstances. Knowledge that this occurs cannot therefore influence the priority given to a particular site. The same argument applies to damage-only accidents, except more so, because far fewer are reported. Personal injury accidents reported to the police are used to identify the roads where the problems are most severe, so that resources can be targeted to greatest effect.
Residents' accounts of accidents are often not reliably comparable from one site to another. In assessing the seriousness of an accident, obviously some predetermined and universal standard must be applied, and it is difficult to assess accurately a member of the public’s description of events within such a framework.
The accident data we receive from the London Accident Analysis Unit (LAAU) gives us details of the road conditions at the time of the accident (i.e. was it wet/icy/ dry/daylight/dark etc) and the probable causes of the accident. The data is confidential.
Since the Council put speed humps in my road there has been an increase in traffic vibration. What can the Council do?
Whilst the Council recognises that noise and vibration from heavy traffic is a nuisance, it is in fact very unlikely that any damage would be caused to your property. Vehicle damage to buildings is almost unknown except in cases where the vehicle actually hits the building.
The Transport and Road Research Laboratory have established that even in the worst case with respect to ground conditions, type of vehicle and state of loading, structural damage can not be induced further than one metre from the line of the nearest wheel track.
If you are still concerned, having read this information, please contact us by email or in writing to The Highways Maintenance Team or by phoning CallPoint. We will arrange for a highway inspector to check that the dimensions of the humps comply with the regulations and that there are no defects in the road surface that is making the problem feel worse.
Why is there a bus route on my road – it is a residential road?
The Council has a policy of encouraging bus companies to run services into residential areas to encourage the use of public transport instead of private cars. The use of buses reduces the overall number of vehicle trips along with the congestion and pollution the cars would have caused.
Where buses run and which type of vehicle is used on each route is decided by London Transport and the individual bus companies concerned, and not by the Council.