Help Forum

Help requested posted on 30th December 2019:

20 mph residential speed limit

Brockworth Parish Council has passed a resolution to introduce a 20mph residential speed limit for Brockworth. However, the Council have only allocated 5000 for the project, obviously further funds will be required if progress with the proposal is to be made. Where may more funding be obtained?

Scott Mc Neill
West Ward Brockworth Parish Councillor

scott mc neill

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Response posted on 2nd January 2020 by:
Rod King

T: 07973639781

20 mph residential speed limit

The responsibility for setting a local speed limit is with the appropriate Traffic Authority. This would therefore be Gloucestershire County Council. A Traffic Authority does not have the power to set a local speed limit unless it has appropriate grounds. There is no provision within the DfT Guidelines for taking into account the cost of setting an appropriate limit. The appropriateness of a limit is therefore not conditioned by whether the Traffic Authority, local parish, or any other part of local government has any funds allocated for it.

The setting of a local speed limit is therefore a two stage process :-

1. What is the appropriate limit? Is it 30mph or 20mph.

2. How is this to be funded.

There is no provision to abdicate responsibility for setting a 20mph if it is considered appropriate based on its merits because funding may be difficult or may have been unplanned.

Hence the answer is that Gloucestershire County Council have to find the funds. This may come from many sources. Traffic Authorities have used :-

Section 106 funding
Development funds
Highway capital funds
Active travel funds
Public Health funds

Response posted on 2nd January 2020 by:
Miss KM Carpenter


20 mph residential speed limit

It's important to understand what 20mph signed-only limits (no humps bumps chicanes etc) do and don't do. Some councillors, members of the public etc believe they reduce speed a lot - people often tell me they expect 10mph speed reduction as the limit falls by that much. In practice the change is beneficial but modest: from the major study undertaken for DfT the effect was as follows: "The journey speed analysis shows that the median speed has fallen by 0.7mph in residential areas and 0.9mph in city centre areas. Faster drivers have reduced their speed more, with the 85th percentile speed falling by -1.1mph in residential areas and by -1.6mph in city centre areas, based on journey speed data. This is a key finding, as other research shows that higher speeds are associated with increased safety risk (more collisions, increased severity, perceptions that the environment is not safe for vulnerable users)." A 1mph speed reduction - the most you should expect - can reduce casualties by 5% which is beneficial, and lower speeds might encourage people to walk or cycle but such small changes are very unlikely to be detectable which is why little if any effect on journey behaviour resulting from speed reduction was found. This doesn't mean 20mph limits are not helpful, but their measurable effect is modest and at cost and environmental impact of new electrically illuminated signs (must be bought, installed, maintained and powered, electricity bill ever increasing), new markings, legal orders and staff time and cost to design the signs and write the orders. The total cost can be surprisingly high, and may not be the most cost-effective way of reducing casualties - other engineering measures often have a higher casualty reduction per 1000 spend, and the highway authority has their entire network to manage, though they may allocate specific sums to each parish. Ethically this means spending money for greatest public benefit (casualties; pollution; severance/community impact etc). Being a highway authority is like running a country with the budget of a county, the choices are extremely difficult and budgets always reducing. This is the context in which Gloucestershire finds itself and I don't envy them! If there are few speed-related casualties at present - see - especially pedestrians/cyclists - this would reduce the cost benefit. Lots of the casualties in the parish look like low-speed incidents; (e those on roundabouts of minor roads) but others eg on straight major roads could be speed-related - these should be analysed in detail to determine the likely actual effect) Some roads like A46 - where a pedestrian fatal 3 years ago may indicate high speed?- would be extremely unlikely to be plausible 20mph limits to the public so compliance would be low unless you include camera enforcement - another significant expense as multiple sets of average speed cameras would be needed. No easy questions or easy answers!

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