20mph Signage Regulation Changes

Signing 20mph speed limits has become easier and dramatically cheaper. Repeater signs are now optional. Half the terminal (start/end of limit) signs are required. A minimally signed scheme stipulates 70% fewer capital items. Total costs fall by 40%. Cost per head falls from £2.50 to £1.50

Traffic Authorities are required to sign speed limits clearly to drivers which helps police to uphold speeding offences. Boundary signs showing 20mph signs can display the community wish for slower speeds. In May 2016 the Department for Transport updated its Traffic Signs Regulations and General Directives (TSRGD)[1].   Changes for 20mph limits:-

  • Repeaters – The requirement for at least one repeater (reminder) sign was removed.
  • Terminal Signs - Two terminal signs used to be needed. Now it’s only one and can be either side.
  • Fewer New Poles – to display signs are needed due to fewer signs as above.
  • Reducing or relocating terminal signs is allowed after a robust risk analysis.
  • Lighting – only terminal signs from trunk roads need be lit.
  • Fewer Warning signs are needed in slower speed limits – eg ‘slow down’ for vulnerable people.
  • Less Maintenance of Fewer Signs - ongoing costs potentially fall even after costs of removal.

The table below lists signage capital items in the tender for Edinburgh’s South Central 20mph scheme. Signage was £113k (52%) of the total £214k budget[2]. Under new signage regulations a minimum of only 275 (instead of 1200) capital items are required.  A whopping 77% fewer!




2017 minimums

Terminal signs


225 – no need for pairs of signs. 1 or 2 as desired.

Repeater signs


0 – entirely optional



50 – fewer signs to display, which can be either side



0 – entirely optional

Total capital items


275 (77% fewer as a minimum)


New regulations allow Traffic Authorities more freedom to install signs appropriate to the circumstances, e.g. to reinforce a lowered limit in marginal locations.  Reinforcing a 30mph limit makes more sense where 20mph is widespread, for instance by using 30mph reminder/speed camera signs (Diag 880).

Once the policy of wide 20mph is democratically agreed, signage costs are now almost entirely incurred due to changes up from 20mph.  A big, inclusive 20mph scheme, with a higher proportion of roads included, is better value for money.  Wide area 20mph schemes with few exceptions are now anticipated to cost £1.50 per head instead of the previous average of £2.50 per head, about 40% less overall. Which authority will install a minimally signed 20mph scheme first? We predict others will follow suit.  When costs fall, the benefit to cost ratio usually rises giving even better cost effectiveness / value for money!

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  • Rod King
    commented 2018-09-09 18:35:22 +0100
    Dear Graham

    You will be pleased to know that on entering a 20mph limit or zone there is a large sign that is 600cm across or in diameter. In old units that is 2ft wide. Hence there is no reason why an aware driver would not notice such a sign. Its the same size as when you enter a 30mph limit. Indeed, it iss the same size as the one you say you noticed on exiting a limit.

    20mph limits are now very common and 25% off the UK population live in local authorities where 20mph is the limit on most roads. Hence a 20mph limit should not be surprising at all. May I therefore suggest that if you feel that you may well not notice such signs then you should assume that the speed limit is 20mph and only proceed faster if you have noticed a 30mph sign.
  • Graham Palmer
    commented 2018-09-05 18:42:44 +0100
    The change in regulations might make it cheaper to implement 20 mph limits but at the expense of drivers who do not notice. It is difficult enough in unfamiliar town centers when a driver is trying to follow signs to the town center, car parks, visitor attractions and making sure he is in the correct lane let alone noticing the reduced speed limit to a surprising 20 mph. I have on a few occasions only noticed the 20 mph limit on leaving a zone. I like to follow the rules but need to know what they are so I can follow them.