An Analysis of Before and After Pedestrian and Cycling Surveys in two Pilot Areas of Bristol with 20mph Signed-only Speed Limits by Malcolm Heymer.
This detailed analysis of claims that seemed unlikely to be correct exposes many astonishing and unnaccaptable errors in the way the raw data was collected and analysed.
Sadly typical of the entire 20mph bandwagon, see also 20′s Plenty Nonsense