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Understanding Speed Limits

By: - Updated: 19 Aug 2013 | comments*Discuss
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The UK is well known for having one of the best and most admired road safety records in the world. This could be partly due to the speed restrictions that we impose on the road network throughout the country with the intention of encouraging safer and more responsible driving.

A History of Speed Limits

Britain's Speed Limits have come a long way since 1865 when the Locomotive Act restricted the speed of horse-less vehicles to 4mph in open country and 2mph in towns. The act required 3 drivers for each vehicle - 2 to travel in the vehicle and 1 to walk ahead of it carrying a red flag. Hence the Red Flag Act was born.

Speed restrictions as we know them today came into force over 60 years ago in 1934 when a 30mph limit was brought in for roads considered to be in 'built-up' areas. This particular limit is still used today.

Other roads had no limits, until 1965 when the Minister for Transport introduced a 70mph restriction for all roads, which included highways and motorways.

In 1977 the speed limit for cars and motorbikes on dual carriageways was set at 70mph with single carriageways carrying a 60mph limit.

The limits remained untouched apart from a few exceptions, until 1999 when local authorities were allowed to bring in 20mph speed limits without needing to get permission from the Secretary of State.

So Who Sets the Speed Limits in the UK?

The Highways Agency sets speed limits on motorways and the trunk road network. The Government also offers advice to traffic authorities on which speed limits to set in their individual areas. They take into consideration local circumstances and issues and based on their findings, decide on an appropriate limit for their roads, which can be between 20-70mph inclusively.

The Different Speed Limits and Where to Find Them

20mph Speed Limit
Introduced in 1999 and set by local councils, the 20mph limits are mostly used in urban areas, such as residential roads (particularly narrow ones), town centres and around schools and nurseries. The reasons are obvious - where there is a high concentration of pedestrians, it makes sense to keep the limits slower to avoid collisions and accidents. Usually the 20mph will come under a 'zone' which will combine other traffic calming measures like speed humps with the lower limits.

30mph Speed Limit
Also seen in urban areas and villages since its introduction in 1934, there will only be a sign at the beginning of a 30mph zone. This is because roads under this limit are easily identifiable by a system of streetlights. This in itself confuses people despite being rather simple - here's what you need to remember: the 30mph speed limit applies to all traffic on all roads with street lighting unless road signs show that a different speed limit applies. If the road is unlit then there will be repeated 30mph signs along or beside the road for the duration of the limit area.

40mph and 50mph
Introduced to be used in non-built up areas where a higher speed is considered to be safe and appropriate. The beginning of the speed limit must be clearly signed and repeater signs must be placed at regular intervals along the length of road that the limit pertains to.

National Speed Limit
When you enter an area that is signed by a diagonal black stripe on a white background, you are driving under national speed limit restrictions. For most vehicles this will means 60mph on single carriageway roads and 70mph on dual carriageway roads. It is also 70mph on the motorway network unless otherwise indicated.

Temporary Restrictions
Temporary speed restrictions are often put in place to encourage safer driving during road repairs with the intention of making the area safe for those working there. When on Motorways and faster roads they are usually enforced by very visible warning signs and speed cameras.

Speed Limits, Not Targets.

It's important to remember that a speed limit is just that - the top speed that you can drive at on any particular road. It's not a target speed, and just because you are allowed to drive at a particular speed, doesn't mean that it's always going to be safe to do so. For example: 70mph may be fine on a sunny day, but dangerous on an icy, snowy winter morning.

Many factors other than speed come into safe driving, so remember that working out your 'safe speed' will be a continuous assessment for the duration of your drive. With this in mind, take care to ensure that you adjust your speed in accordance with the road conditions and stay always stay within the limits.

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all very interesting mmmm. When are we all going to wake up.the polititians are using all these rules to raise revenue,otherwise rip us of for every penny they can. ALL IN THE NAME OF ROAD SAFETY. We as drivers know that it is unsafe to use handhelds when driving so fit hands free kits,they are quite low in price. The police are being used by the polititians to be revenue collectors.and in my and many others opinions are totally out of control.they are stopping drivers for the slightest thing and try tactics like take a fixed penalty as going to court will cost you more, go to court jam up the system with cases they will have to give up in the end.Remember at the next election which two parties are making this happen are have more in the pipeline.Would the French put up with non,this country went through a war to stop this kind dictatorship a lot of good all that sacrifice did.Anyway stay calm and remember"don't let the bas----s grind you down
jamlog - 19-Aug-13 @ 5:16 PM
Hubby got camera-ed doing 35mph in 30mph zone whilst decelerating into it. I remember a TV prog on the traffic cop in his speed camera van saying that he allowed 10% + 3mph so technically hubby was still within the allowable speed or was he?
Loobylou - 2-Aug-13 @ 8:59 PM
I was camered doing 35 in a 30 zone. Is there an allowance like 10% + 2 mph or am I confusing this with the 70 limit?
Richard Walker - 1-Oct-12 @ 1:44 PM
I have driven 45 years without a speeding conviction and then received 2 in just 4 months, both eligible for 'speed awareness courses'! I would like to know who runs these courses and where does all the profit go to? They seem to be a licence to make money!
Colino - 8-May-12 @ 1:50 PM
Are 20mph speed limit signs, circular with a green border, enforceable or do they need to have a red border?
smithster - 9-Mar-12 @ 8:51 PM
Is the national speed limit in a lit street 30mph. On some routes you pass from a 30 to a national speed limit, but there are street lights - does this imply that the speed limit is still 30mph? stan
square on the short - 6-Nov-11 @ 10:50 AM
Can anyone tell me why the National speed limit does not apply to Scottish Motorways? (Notice South of the border there is a NSL sign and Crossing it becomes 70? Confusing eh!)
The Boss - 7-Aug-11 @ 1:33 PM
Bourbonbot has summarised it well. Am a very careful driver, but got caught by a mobile unit (Speed had changed from 40 to 30 !). Attending speed awareness course tomorrow, but wholeheartedly agree a revamp and simplification is most definitely needed. Matters have become worse by new signs that say "variable speed limits apply". What is the limit that one should follow on such a road?
tas - 27-Jul-11 @ 12:12 PM
The UK road laws are draconian and need a major revamp. In other countries it's law to have your headlights on when using your wipers, what a great idea! Our speed limits are so variable and not clear enough. I have fallen victim to our petty mobile cameras who themselves disregard the law - parking illegally in order to catch motorists. Not displaying signs to say they are there and not being out and visible. I am going to a speed awareness course as a result. I am not a speeder and tend to drive at least 5mph under the limit if not more. But due to the changing speeds I was caught between a 70mph and a 50mph and I was gunned at 61Mph whilst slowing down. Keerching!!! 85 pounds please. This country needs to have a good look at the whole system and bring us up to date with the world we live in.
bourbonbot - 8-Apr-11 @ 11:50 AM
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