Most Drivers Ignore 20 MPH Speed Limits

A new report from the Department for Transport (DfT) shows that the vast majority of drivers ignore 20 MPH speed limits. A survey of nine sites across the UK showed that 81% of drivers exceeded the 20 MPH speed limit in the report entitled “Speed Compliance Statistics”. This might explain why the impact on average speeds by introducing signed only 20 limits is negligible as reported in a previous article on this blog, or that the impact on actual accident statistics as reported in many such zones is also not apparent.

The DfT report also notes the common failure to comply with the 70 limit on motorways, although compliance with other speed limits seems to have slightly improved. There has, of course, been wide calls for an increase in the motorway limit.

Surely the message here is that imposing unrealistic limits tends to be ignored by drivers. We have always supported setting speed limits at the 85th percentile of free-flowing traffic speeds so that only those drivers who are clearly not adhering to what most drivers perceive as “reasonable” are potentially penalised for breaking the law. In addition, it has been shown in other studies that setting the limit in that way is likely to be safer than artificially reducing the limit.

So those London boroughs who are dogmatically introducing 20 limits everywhere (such as Lewisham and Croydon) should take note. The hundreds of thousands of pounds they have spent introducing such “signed only” limits is a waste of money that would have been much better spent on other road safety initiatives. But regrettably those who have signed up to the religion of lower speed limits seem immune to listening to reason and to understanding the facts.

Roger Lawson