LIKE flies on a muggy summer’s day, Net Zero nonsense constantly pesters you. There are so many things one could be doing if one weren’t swatting the blighters, but for a less troublesome life there is no alternative to taking out as many of the critters as one can.
And so I turn my attention to the buzzing nuisances that are 20mph speed limits. Sir Sadiq Khan has been jumping up and down recently about the great success of such schemes and bragging about how much more he is going to spend on them.
As with his claims on the success of the Ultra Low Emission Zone, the headlines aren’t supported by the facts. Yet again, Transport for London (TfL) are marking their own homework, producing a report justifying their previous expenditure to support more of the same. Trying to find the evidence supporting these claims is not straightforward; if you want some nice infographics to parrot the London Mayor’s spin, they’re there on the same webpage as the press release extolling this initiative’s supposed success. The detail is harder to locate but with a bit of persistence one can find the data file which reveals a more complicated reality.
The claims of a 35 per cent reduction in the number of collisions and 32 per cent reductions in deaths and serious injuries come from a review of 157 traffic schemes implemented between 1989-2013. TfL looked at road accident statistics for the three years before and after each scheme’s implementation to identify collisions and injuries. Due to changes in 2016 in how injuries were recorded, TfL ignored more recent initiatives as data pre and post 2016 may not be comparable. So far, so good.
A list of schemes is provided with the date each was implemented but they are given code names so one doesn’t know where these schemes were/are. The list does not make the most basic distinction between initiatives: 20mph limits (usually little more than signage) and 20mph zones (incorporating a variety of traffic calming measures). In practice, road schemes often include several measures intended to improve safety, such as better sight-lines at junctions, of which speed limits may only be a small part.
Taking the 157 schemes together, there was a 35 per cent reduction in recorded collisions in the three years after implementation compared with the three years before. However, 16 per cent of the schemes saw no reduction in collisions and in 18 per cent of them the number of collisions increased. There was a similar pattern for fatalities and serious injuries arising from these initiations: 44 per cent of schemes saw reductions, in 36 per cent there was no change and in 20 per cent of them there were more fatalities and serious injuries after they were introduced. So at least one in three of the schemes, and arguably more than half, were a waste of time and money. It would be interesting to know why some schemes didn’t work but you wouldn’t be aware of these failures if you only read TfL’s report.
Such nuance doesn’t suit Khan’s and TfL’s agenda of more speed restrictions. They won’t dwell on anything that might question their predetermined conclusions. Their own analysis acknowledged the 20mph schemes had no impact on motorcyclist injury numbers but there’s no attempt to explain this anomalous result. While their report presents the research showing where 20mph schemes are claimed to have worked (eg Edinburgh and Bristol), they make no mention of the Belfast scheme that didn’t have any noticeable benefits nor the decision by Manchester City Council in 2017 to stop all 20mph schemes as their analysis showed they had no impact. Nor do TfL mention a 2018 study commissioned by the Department of Transport which found – looking at data between 17 and 42 months after the implementation of 20mph schemes – that there was no significant change in collision and casualty numbers.
Let me give you a succinct, honest appraisal of 20mph schemes: I don’t know if they work and neither does anyone else. Most likely some do and some do not. As they are often implemented with other measures to improve road layouts, the impact of a speed limit reduction alone is difficult if not impossible to assess accurately. And even if they have worked in the past, there’s no guarantee they’ll work in the future. The first schemes are likely to have been targeted at the worst accident blackspots so new schemes will probably offer diminishing returns.
But none of this matters to the eco-nuts. If it makes life more difficult for car drivers it must be good and anyone who doesn’t agree wants children to die crossing the road. 20 is Plenty for Us is how one pressure group styles itself, except that 20mph isn’t plenty for some. Already the push for 10mph speed limits is coming. The Net Zero zealots hope this will drive (pun intended) people out of their cars. Not me. To paraphrase Charlton Heston, they’ll have to pry the steering wheel out of my cold, dead hands.
