An item about a 20mph petition circulating in the town has been received:

20mph sign 1 smRecently houses in Whitchurch have had leaflets delivered claiming that “Casualties increase in 20MPH zones“.

The leaflet encourages residents to sign a petition at Payne’s Printers to re-instate the 30MPH limit ‘except near schools’, and states that “Most of Whitchurch’s businesses have signed“. The headline of the leaflet is ‘30MPH Reduce the accident risk‘.

The leaflet cites a press release from the Institute Of Advanced Motorists (IAM) on July 4th 2014, essentially claiming that 20MPH roads are more dangerous than 30MPH roads.

This claim was investigated by Radio 4’s statistics program ‘More Or Less‘, lead by The Economist’s Tim Harford, and was found to be ‘Phonus Ballonus‘ – the BBC analysis can be listened to HERE (from 12′ 20″).

Aside from the claim that 30MPH is safer than 20MPH, the petition publisher suggests that Whitchurch children and parents only need protecting from 30MPH vehicles ‘near to schools’.

The petition publisher offers no suggestion on how parents and children get ‘near to schools’ without walking along or crossing roads with 30MPH traffic.



The basics of the Radio 4 article is that the IAM press release ignores the significant growth in the number of 20MPH roads, and instead focuses on the raw numbers. According to the BBC, without the context of knowing there were significantly more 20MPH roads in the areas surveyed, the fact that slightly more people were hurt on them is worthless and is no basis to claim that 20MPH areas are more dangerous.

The same IAM press release was used in an advertising campaign by a Brighton & Hove motoring pressure group, ‘Unchain the Brighton Motorist’. Complaints were made to the Advertising Standards Authority. The complainants, who understood there had been an increase in the number of roads with a 20 mph speed limit during 2013, challenged whether the ad was misleading.

In November 2014 the ASA found that the claims made were misleading, and issued the following ruling (it can be read in full HERE):

…we considered the presentation of the claims was such that it misleadingly suggested the government statistics had determined there to be a direct relationship between a 20 mph speed limit itself and the increased number of casualties on those roads.

The ad breached CAP Code (Edition 12) rules 3.1 and 3.3 (Misleading advertising), 3.7 (Substantiation) and 3.9 (Qualification).


The ad must not appear again in its current form. We told Unchain the Brighton Motorist to ensure they did not make claims, including implied claims, about the relationship between speed limits and casualties in future if they were not in a position to substantiate them.



Hampshire County Council have previously advised that:

  • Each pilot scheme will be assessed approximately 12 months following completion which will include the collection of traffic data and a questionnaire to each household. The attached link below is to an update report,  which gives more details about how the pilot programme was developed and how it will be assessed.  This link is on the external Hampshire County Council website so it can be sent to and accessed by the public.

  • The main point is that the scheme assessment will include a repeat questionnaire so all residents within the speed limit area will get an opportunity to formally express their views.
  • If you have any further enquiries on the pilot, please contact the  traffic management team,