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          Speed Safety


Compliance with Speed Limits
In an ideal world all drivers would obey all speed limits at all times. Unfortunately we do not live in an ideal world and for any number of reasons drivers do from time to time fail to stick to the posted limit.

Over the years a number of measures have been developed to help drivers stay within the speed limit in force. These measures have the effect of changing the nature or appearance of the road to encourage drivers that a slower speed is appropriate. Local authorities have all the necessary powers to introduce any measure they deem appropriate, but obviously which one would depend on the nature of the problem.

Road humps are the most commonly used and most effective measure, reducing speeds by up to 10mph. They are most effective on urban roads, around schools and in residential areas.They are not usually appropriate for rural areas. Other measures include build outs or chicanes that narrow the road thereby encouraging lower speeds, or road markings that have the visual effect of narrowing the carriageway.

Where there is a need to warn drivers to reduce speed when approaching a hazard, vehicle activated signs have proved to be very effective.These are signs that remain blank until a vehicle approaching at a certain speed triggers a message to be displayed electronically.These signs can be very effective on rural roads where the national speed limit applies but drivers need to slow down considerably to take account of a crossroad, a sharp bend or other hazard.

Ideally, all drivers obey the speed limit in force.And where compliance is an issue, some form of intervention measure, such as traffic calming or road realignment would be introduced that persuades drivers to adhere to the posted limit.

However, there are roads where there is a history of accidents but where conventional traffic calming or other forms of persuasion are unsuitable or have proved ineffective. On these roads there may be no alternative but to provide an increased level of enforcement. The most common form of enforcement is safety cameras. The purpose of cameras is to deter speeding at sites where speed related accidents have occurred, not to catch drivers speeding. The police are responsible for enforcing the speed limit and may use any Home Office approved equipment.Apart from traditional fixed speed camera housings, the three most common ways to enforce speed limits are:

a) in-car speed measuring systems operated by a police officer, which measure the average speed of a suspected speeding vehicle over a given distance.

b) handheld speed measuring equipment where a police officer measures the speed of passing vehicles with a ‘radar gun’.That officer will work in tandem with a colleague, positioned further along the road concerned,who will be responsible for stopping any offending vehicle and informing the driver of his speed; and

c) portable speed detection devices which are trained across a road by a supervising officer to measure the speed of any vehicle going through the ‘line of sight’ of the device.

A second ‘stopping’ officer can pull over a speeding vehicle if so requested by the officer monitoring the device.

These devices may also have photographic recording ability, allowing the police to send notifications and requirements to the registered vehicle keeper.

Changing Attitudes
There are various reasons why people speed.

Some are simply excited by driving fast.They can be easily affected by motoring magazines and programmes that highlight the top performance levels of some vehicles.

Motorists in general simply regard the breaking of speed limits – at least in a minor way – as not a very serious matter.Those caught speeding are considered to be ‘unlucky’. But the consequences of driving too fast can be very serious. Being involved in a collision can result in death or serious injury.

Successive governments have set targets to reduce road accident casualties and it is clear that, increasingly, these cannot be achieved without reducing the number of people killed or injured as a result of speed. Long term publicity campaigns are aimed at making drivers and riders aware of the dangers of excessive and inappropriate speed and the substantial safety benefits that can be gained by even small reductions in speed.

In brief:
Facts and figures Because the dangers are so severe, a number of measures have been developed to persuade drivers to slow down. These measures are not always popular but nevertheless they do work.

20mph Zones and Limits
20mph Zones

-Average speeds within zones reduce by 9mph and accident frequency reduces by 60%
-Overall reduction in child accidents = up to 67%
-Overall reduction in cycle accidents = up to 27%
-Traffic flow within zones reduced by up to 27%
(Source TRL Report 215 - “Review of Traffic Calming Schemes in 20mph zones”)
20mph Limits
-Speed limit signing without supporting traffic calming measures reduction of an average of 1mph.
(Source TRL Report 363 - “Urban Speed Management Methods”)

Road Humps
-Road humps in their various forms achieved the biggest mean speed reduction (based on a mean speed before traffic calming of 30mph)
-100mm high raised junctions (Commonly known as speed tables, these are large flat topped humps that straddle the entire junction.) achieved biggest reduction of up to 12mph and subsequent likely accident reduction of 60%.
-75mm high flat-top road humps and 80mm high round-top humps achieved a 10mph speed reduction and a likely accident reduction of 50%.
(Department recommends 75mm road humps as achieving best speed reduction with least negative impacts).
(Source TRL Report 482 “The Impacts of traffic calming measures on vehicle exhaust emissions”)

Vehicle Activated Signs

Vehicle activated signs are predominately used in rural areas.They are an electronic sign that flashes a message to the driver if a predetermined speed has been triggered.
Research has shown them to be very effective at reducing speed and collisions at hazards such as sharp bends and junctions with poor visibility.
They are also sometimes used to remind the driver of the speed limit in force.
Their effectiveness can be broken down as follows:
-Mean speed reductions at speed limit roundel signs of between 3-9mph

-Mean speed reductions of up to 7mph at junction and bend warning signs

-Mean speed reductions of up to 4mph on safety camera repeater signs

-Overall one-third reduction in accidents at trial sites (Norfolk sites)
(Source TRL Report 548 - “Vehicle Activated Signs - a large scale evaluation)

Effects on casualties at camera sites:

-A 40% reduction in the number of people killed or seriously injured (KSI)

-870 fewer KSIs per year, including over 100 fewer deaths

-a 33% fall in injury accidents – 4,030 fewer per year

-35% reduction in pedestrians killed or seriously injured Effect on speed

-average speeds at all new sites fall by around 7% or 2.4mph;

-average speed at urban sites fall by around 8%

-the number of vehicles speeding at new camera sites drop by 71%

Other findings
-79% of people asked support the use of cameras to reduce casualties

-the benefit to society through casualties saves about £221 million per year
(Source:The National Safety Camera Programme Three-year evaluation Report - June 2004)

For further information on Speed and other road safety issues you can visit the THINK! campaign website at: or for information covering the Department of Transport as a whole visit

Drivers with speeding points aren’t more dangerous says Safe Speed

Research commissioned by 8 midlands camera partnerships, published today, claims that drivers with speeding points are more crash involved.

Safe speed points out that many insurance companies - working from comprehensive data - disagree. They do not load the premiums of drivers with speeding points.

That isn’t the only problem with the claims.

• Although the claim is being made that there has been some correction for ’risk exposure’ (obviously drivers who do higher mileages are more exposed to the risk of crashes and more exposed to the risk of speeding convictions) we have no confidence that the correction has been carried out properly. After all, for an insurance company, you would think that speeding convictions would function as an exposure proxy. Because of the greater exposure we DO expect those with more convictions to be more crash involved. But if many insurance companies are not even finding that effect, then it seems likely that mile for mile, those with speeding convictions are LESS likely to be crash involved.

• If speeding convictions made drivers safer, then we should expect the opposite effect to that claimed. Convicted drivers should have become safer. If convicted drivers are more crash involved then clearly the system isn’t working to make the roads safer.

Paul Smith, founder of the Safe Speed road safety campaign ( said: "I believe that this research is nonsense, strongly influenced by pre-conceptions and vested interests. Speed cameras do not identify risky drivers nor do they make our roads safer."

"It’s junk science, and junk science makes our roads more dangerous because it tends to cause life-saving resources to be misallocated. This is the
fundamental reason that speed cameras have proved to be a road safety disaster .
Everyone - drivers, police, highways authorities and many road safety groups - are expending resources on the wrong safety factor. Had those same resources been allocated efficiently, we would now be down to around 2,000 road deaths per year. We’re over 1,000 lives a year behind schedule and I am certain that speed cameras are at the centre of the problem."

"Our speed cameras are all in the wrong places - they should be in the scrap yard."

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