Proposed 20mph area for Chorleywood

Results of the Consultation – November 2022

(Reprinted from newsletter 25th November special edition)

In the summer of 2021, Hertfordshire County Council asked residents if they wanted 20mph limits on most Chorleywood roads, except the faster ones such as Shire Lane, Blacketts Wood Drive and Green Street.

We have just heard the result of the consultation – Chorleywood residents rejected the scheme, but residents clearly supported a 20mph limit on the key trouble spots: Chorleywood Bottom, Stag Lane as far as Chorleywood Primary School, Bullsland Lane and Old Shire Lane.

CRA worked extremely hard to understand the implications of the proposals and inform Chorleywood residents of the impact of the original proposal.  The scheme would have meant over 40 change of limit signs dotted all around Chorleywood, and research shows that such schemes have little effect on straightforward local roads.  We agree a focussed scheme on the known trouble spots, especially Chorleywood Bottom and Stag Lane, will be much more effective, while also hopefully faster to implement and at lower cost.

We’re very pleased that local residents had full information from us on which to make their choice.  The decision to make Stag Lane 20mph will also make it easier for Hertfordshire County Council to introduce a much-needed zebra crossing outside Chorleywood Primary School, for which we had already urgently pressed the case.

We hope the new speed limits and zebra crossing will be implemented very soon – we will update you through our newsletter as soon as we hear more!

Consultation – Points to Consider – Summer 2022

(Updated 29th January 2022)

We understand and respect that residents will have differing views on this topic.  We believe it is vital that all residents are fully informed on the issues and details of the proposals, before responding to the consultation on this important issue which affects our whole village.

The consultation process

  • Every response counts. If you have a view, for or against, please make sure you respond.
  • The imminent 20mph consultation is the second consultation on the 20mph proposal, the first was in March 2020.
  • The consultation will be open to anyone who wishes to respond.[1]
  • Responses are from individuals, not households.
  • The scheme will only progress if at least 55% of respondents are in favour.

The proposal

  • The proposal is to limit all roads in central Chorleywood to 20mph, except Shire Lane, Blacketts Wood Drive, Chalfont Lane, Green Street, Carpenters Wood Drive, St Peter’s Way and Whitelands Avenue beyond the junction with Blacketts Wood Drive.
  • Hertfordshire County Council’s Speed Management Strategy says “20mph areas without additional traffic calming measures will only be considered where the existing mean speeds are 24mph or below”.[2] This is why Shire Lane, Blacketts Wood Drive, Chalfont Lane, Green Street, Carpenters Wood Drive etc are not included in the 20mph proposal.
  • HCC’s Speed Management Strategy also says that “All consultation documents will state that a 20mph limit or zone will generally be self-enforcing with little or no police enforcement”.[2]

 Signage vs focused measures

  • A 20mph area requires change of limit signs and road markings at every transition point from other speeds. In areas with lampposts, as Chorleywood does, 20mph repeater signs would also be required at least every 200m.[3]
  • We believe this would mean about 40 speed limit signs at junctions in the centre of Chorleywood plus a large number of 20mph repeater signs.
  • We’ve campaigned for focused measures in problem areas, such as Stag Lane by Chorleywood Primary School and Chorleywood Bottom.
  • If the trouble spots are addressed with focused measures, do we need extra speed limit signs at so many junctions, on roads where existing mean speeds are 24mph or below?

 Reported accidents

  • The recent Chorleywood Voice newsletter said “50 accidents on our roads have been reported to the police in recent years”.   This number surprised us, so we investigated.
  • Both police and HCC official data confirm that there have been 5 reported injury accidents on the roads in question from 1 October 2016 to 30 September 2021.
  • All were rated “slight” and, importantly, none were speed-related.
  • Many more injury accidents were on the M25, A404 and other roads which are not part of the 20mph proposal.  Click here for a map.
  • There is no official count of other incidents reported to the police for insurance purposes.
  • We have asked for and await details of an official and verifiable source of the “50 accidents on our roads reported to the police” claim.

A 20mph Limit or a 20mph Zone?

  • What is proposed is a 20mph limit area, which can only be implemented on roads with average speeds of 24mph or less, and does not include traffic-calming measures. ie: no cameras, speed bumps or chicanes.
  • A 20mph zone covers a complete area and includes traffic-calming measures on roads where existing mean speeds are higher than 24mph.

Department of Transport research

  • The Department for Transport commissioned Atkins, Aecom and Professor Mike Maher (UCL) “to address a gap in the evidence available on the effectiveness of 20mph speed limit (signed only) schemes.”
  • Twelve case study schemes were studied, from a variety of area types, road types and scale. The report was published in November 2018 & updated in March 2019.[4]
  • From the webpage for the report, the last comment on the webpage says “The research concludes that:
    • 20mph limits are supported by the majority of residents and drivers
    • there has been a small reduction in average (median) speed – less than 1mph
    • vehicles travelling at higher speeds before the introduction of the 20mph limit have reduced their speed more than those already travelling at lower speeds
    • There is not enough evidence to conclude that that there has been a significant change in collisions and casualties following the introduction of 20mph limits in residential areas”.
  • We encourage all residents to respond to the 20mph proposal, and are happy to answer your questions if we can.
  • The most important thing is that every response counts on this important issue which affects all Chorleywood residents.

If you have a view, for or against, please make sure you respond to the consultation.  With or without a letter everyone can respond to the survey, and every vote counts. Abstentions don’t count either way.  And your comments count! The survey asks for comments, which will be considered and can change the outcome.   

Reference documents that we have found useful include the sources below.

Source references

  • Herts County Council’s first consultation letter dated 16th March 2020. This letter went to residents in the roads then envisaged for the proposed 20mph area in Chorleywood.
  • Herts County Council Speed Management Strategy, November 2020
  • DoT Traffic Signs Manual, chapter 5, clause 5.16.10, August 2019
  • “Department of Transport Report into the effectiveness of 20 miles per hour (mph) road speed limits”, which is available online at:,

Briefing Note on 14th September

CRA also sent out a briefing note about this consultation on 14th September 2021.  Click here to see that note.  The information above replaces and updates the September 2021 note.

Respond to the survey whether you support the proposal or not and provide relevant comments by 3rd June 2022

  • Write to Terry Curtis, Postal Point (CHO242), First Floor, East Link Corridor, County Hall, Pegs Lane, Hertford, Herts, SG13 8DN
  • Email to

Clearly state the reference TR00122 at the top.

General enquiries relating to the proposals should be referred to the Highways Engineer concerned – Graham Taylor telephone 07503 941717 or