Crash mis-recording – Our analysis of police crash injury records in 20mph zones

We obtained data from Transport for West Midlands to see what effect Low Traffic Neighbourhoods have in South Birmingham on crash injuries. Unsurprisingly the completed Kings Heath Ph 1 LTN had dramatic success in crash injury reduction (16% compared to city wide trends 2017-2021) – according with equivalent studies across London’s LTNs

. The ‘F2 study area’ in Moseley, where a just few cul-de-sacs were installed as part of the 2020 phase 1b activity but no actual complete Low Traffic Neighbourhood was set up, did not produce any noticeable changes for better or worse than previously – LESSON: Deliver complete LTNs to save lives and reduce injuries

BIZARRE FINDING : Analysing the data, derived from police recorded STATS19 records did reveal one very strange, and disturbing, finding. Most of the injury crash incidents were recorded as happening on 30mph roads, whereas the two zones studied were overwhelmingly 20mph zoned roads (this included the hot-spot of Kings Heath High Street and the A435 between Highbury Park and Howard Rd). These roads were desighated as 20mph zones as part of the Birmingham Cycle Revolution funding in 2015-2016.

We analysed the records, road by road, and found the follow level of mis-recoding

Original Data sources for this are TfWM supplied detailed crash records for :

• the South Moseley proposed LTN ‘study area F2’ for Jan 2017 to Sept 2021 LINK : https://drive.google.com/file/d/1eAssPURwOs8cZybF_vksTimKp74wjwri/view?usp=sharing
• The Kings Heath Low Traffic Neighbourhood over Jan 2017 to May 2022  LINK : https://drive.google.com/file/d/1UtrCofYzZOkVyRAA-SQ0jqs6AONzShTn/view?usp=sharing

These files are the system-generated files from the TfWM RTC graphical analysis tool

See Filecopy2 file for a text based report (excludes much information) or Generic file for the actual STATS19 records including all data fields recorded from crash injury incidents.

Both areas are largely 20mph zones. Some boundaries remained at 30mph following introduction of 20mph zoning funded by the ‘Birmingham Cycle Revolution’ monies in 2015-16., these are treated appropriately in the analysis

The analysis in full including combined TfWM-supplied ‘raw’ STATS19 files available on this link: https://docs.google.com/spreadsheets/d/11p5QnirENnbMhPMZtiZ_h-MrzmQ3o29-/edit?usp=sharing&ouid=115445206626232409181&rtpof=true&sd=true