Saturday 23 August 2014

Limits and Zones


What's the difference between a 20mph Limit and a 20mph Zone?


There used to be a very clear distinction between areas or roads set as 20mph zones or 20mph limits. 20mph zones require any point to be within 50m of a  "traffic calming device" which used to be defined quite strictly as a physical calming device. Whilst 20mph limits only require each point to be within 50m of a repeater sign that informed the driver that the speed limit was 20mph.
This reliance on largely physical calming in zones increased the cost some 50-fold over limits due to the expense of such physical calming. Hence for the same cost of treating a street of 250 people with a physically calmed zone then an entire community of 12,500 could be treated with a wide-area 20mph limit.

However this requirement was relaxed in 2011 when the DfT announced that for 20mph zones then repeater signs, carriageway roundels and mini-roundabouts could also be classed as "traffic calming devices". However any zone should include at least one physical calming device. In limits a carriageway roundel could also be used in place of a repeater sign. Note that the actual placement of roundels and repeater signs is at the discretion of the local authority. See the Special Directions Authorisation Note.

This has made a huge difference to the way that 20mph limits may be set and in practice there may be little difference between zones and limits. Where traffic authorities are implementing 20mph limits the choice of zone or limit will probably depend on the type of street, current vehicle speeds and whether isolated 20mph zones already exist. If they do then it is often more practical to widen expand these in a much larger community-wide zone. Note that 20mph zones have rectangular boundary signs with a 20mph limit sign within it, whereas 20mph limits have round boundary signs.

In order to set a 20mph limit, either as a zone or limit, then the following conditions must apply :-

1) The correct Traffic Regulation Order must be made for the road concerned.
2) Any signage or traffic calming devices (in the case of zones) must meet the Traffic Signs Regulations and General Directions. This specifies the design of signs or traffic calming devices and where they need to be placed.

Once this has been done then such 20mph limit or zone is valid and enforceable by the police. The Association of Chief Police Officers have guidance on this which is availablehere.

The Dept for Transport guidance on setting local speed limits was revised in 2013 and this very much encourages the use of 20mph limits or zones for residential streets and those with high numbers (or potential numbers) of cyclists and pedestrians. This is available here.

Note that the TSRGD is a technical document that must be adhered to, whereas the DfT and ACPO documents are guidance.

Wednesday 20 August 2014

Speed Limits and Street Lighting


What are the rules about 30mph limits and street lighting?


The 30mph speed limit that applies automatically to “restricted roads”  is triggered by there being “three or more lamps throwing light on the carriageway and placed not more than 183metres apart”.

Where there is no street lighting or inadequate spacing then in order to set a 30mph limit then the Traffic Authority needs to implement a Traffic Regulation Oder that specifically sets a 30mph limit. In addition they should also put 30mph repeater signs on such a road to remind the drivers that in the absence of the lighting or any lighting at all then a 30mph limit applies.

There may be some debate as to whether lighting that is permanently turned off is able to “throw light on the carriageway”. However Traffic Authorities are in a position to make a TRO for these so that regardless of the lighting a 30mph limit applies by virtue of the TRO rather than the lighting (or lack of it).

If the Traffic Authority sets a 20mph limit by means of a TRO then this shall apply regardless of the street lighting but will require the appropriate traffic calming or repeater signs at regular intervals.

Note that where the speed limit is 20mph or less then most warning signs no longer require their own lighting and many warning signs are not required at all.

Tuesday 19 August 2014

Enforcement of 20mph Limits

Here is my first post responding to an email I received today:-


You offer assistance with any claims by police forces that 20mph limits (zones?) are not enforceable. Any advice concerning the following would be appreciated.

The County Councillor was recently reported as saying that the police have advised him that the local 20mph zone is not enforceable and the only action that can be taken is to charge a motorist exceeding the 20mph limit with dangerous or careless driving. Currently he is refusing to explain his remarks. The minutes of a recent meeting of the parish council record ”due to recent changes in legislation/regulation the Parish Council may apply for enforceable action against speeding in the 20mph zone” and “Update from Police: Recent change in legislation has enabled enforcement codes for individual 20mph zones to be applied for”. Currently the chair of that meeting is unable to explain what was meant. Does any of this mean anything to you?

I am aware of the ACPO Speed Enforcement Policy Guidelines and DfT Setting Local Speed Limits. Currently it seems like a ‘smoke screen’ so any clue to the meaning of these statements and any guidance concerning how to question these statements would be appreciated


We have a long held policy in this country that :-

  • Elected representatives of the community sets laws
  • A professional police force enforces the law
  • An independent judicary sentences offenders

For a 20mph limit to be enforceable there are 4 requirements :-

1. A relevant Traffic Regulation Order

All speed limits, other than those on restricted roads, should be made by order under Section 84 of the Road Traffic Regulation Act 1984. Any speed limits below 30 mph, other than 20 mph limits or 20 mph zones, require individual consent from the Secretary of State. Unless an order has been made and the road is signed to the contrary, a 30 mph speed limit applies where there is a system of street lighting furnished by means of lamps placed not more than 200 yards apart.

Note that there are no regulations regarding how to set a local speed limit. However, the Dept for Transport does provide guidance and this is available here 

Hence the Traffic Authority must make a Traffic Regulation Order to set the speed limit at 20mph. This includes publishing the order so that those affected may object if they wish.

2. Appropriate signing

In order that drivers are aware of the changed speed limit then the appropriate signage must be provided. These are regulations and must be adhered to. The regulations are slightly different for 20mph zones and limits but both must include the appropriate boundary signs where speed limits change and any point in the limit must be no further than 50m from a repeater sign, roundel or physical calming device.

3. Length of road, sighting, equipment

In order for the police to enforce a limit then they require a clear distance for them to observe drivers and for drivers to see them. This may  make certain sites less suitable for speed detection. Different measurement equipment are available. Whilst in the past some "radar" based speed detectors were not approved for use below 30mph, most forces have "laser" type devices that are fully approved for use at 20mph.

4. A Police Force that is willing to enforce

This may seem obvious, and whilst police are becoming far more supportive of 20mph limits and their enforcement, it is clear that in some forces there is a reluctance to enforce. This may be as a result of individual police not understanding the law or a reluctance to commit resources. However as long as the above three conditions have been met then there is nothing to prevent action by the police.

Recently the Association of Chief Police Officers has re-iterated the fact that 20mph speed limits are enforceable and where the limit is clearly marked (ie meeting signage regulations) then any offenders may be prosecuted. The police have also developed the option of speed awareness courses for those exceeding 24mph in a 20mph limit and these may be an option in some forces. Fixed Penalty Notices and prosecutions can also be used. In addition "light touch" enforcement can also be used which merely constitutes a reprimand/talk rather than anything more formal.

I would suggest that the comments about regulations in your question are internal practices within your police force or county council and are not imposed by any outside body. Let there be no mistake, 20mph limits are enforceable and are being enforced by many police forces in the UK.

For a guide on how local authorities can work best with police and other bodies to maximise compliance then see our briefing sheet here