In London, hundreds of miles roads are getting new 20mph speed limits this year. Yet the Government recently announced it may intervene to stop their spread where it believes they are not necessary, while in Wales a new report reveals the effect of its blanket impositions of lower limit.
So what’s going on? Are we heading for 20mph zones across the entire UK, or has the momentum slowed on the idea?
The case for slower speed on roads in return for better road safety is clear, the Royal Society for the Prevention of Accidents believes. It says that a pedestrian hit by a car travelling at 30-40mph is 3.5 to 5.5 times more likely to be killed compared to someone hit by a car travelling below 30mph.
There are more than 20 urban authorities in the UK who have a policy of setting 20mph as the default for their streets according to the pressure group, Living Streets. Greater London is one of the more active authorities in bringing in more 20mph roads.
Transport for London announced in September that 40 miles of roads in Greenwich, Kensington and Chelsea, Lewisham, Southwark, Wandsworth, Merton, Bromley and Lambeth would drop to 20mph over the rest of 2023. In total, by May 2024 it will have made 20mph the speed limit of 80 miles of roads in the capital.
It claims that data collected on roads that had been reduced to 20mph between 2020 and 2022 saw collisions reduced by 25% (from 405 to 304), and collisions resulting in death or serious injury falling 24% (from 94 to 71).
Last year the Welsh Government announced that all residential roads (termed as a restricted road with lampposts no more than 200 yards apart) in the country will have the speed limit reduced to 20mph, with the project costing £32 million.
At the time the First Minister of Wales, Mark Drakeford, said: “We know that 20mph zones reduce speed of traffic, reduce accidents – particularly accidents to children. We want to see that become the default position right across Wales.”
Following their introduction, an interim report has been published looking at eight areas throughout Wales to see what effect the change has had.
It found that on average, speed had reduced by 3mph, while the speed 85% of motorists drive at or below under in free-flowing conditions had reduced by 2.5mph.
Journey time increases, during the morning and afternoon peak periods on routes through the trial areas were minimal and generally not more than one minute.
What the interim results point to is that not much has changed: average speeds are slightly down, overall journey times are slightly up.
One of the crucial factors in these 20mph areas is they are residential streets, with all of the traffic, pedestrians, obstructions, lights and road furniture drivers need to negotiate, and so most probably drive more slowly on average than they realise. As a result, the overall changes are not huge in any direction.
What will prove whether the scheme works is in slowing down those who spend a lot of time driving faster than 30mph, and once evidence has been collected around pedestrian impacts. Every mile per hour can make a difference in those circumstances.
In recent months the UK Government announced it will review policy on 20mph roads in its ‘The Plan for Drivers’ paper.
In it, it said: “To ensure that future interventions on local roads carry the support of the local people, we will update guidance (in England) on 20mph speed limits. While 20mph zones are an important tool in improving road safety in residential areas, over-use risks undermining public acceptance, so we are clear that 20mph zones should be considered on a road-by-road basis to ensure local consent, not as blanket measures.”
And the results of a three year study at the University of Belfast on 20mph speed limits in the city claimed that they have little effect on crashes.
While agreeing that higher speed does have a major effect on the likelihood of serious injury and death for pedestrians involved in a collision, it found that collisions and traffic volumes reduced slightly, but casualty rates fell by 16% after one year of 20mph being introduced, and by 22% three years after.
It said this was not ‘statistically significant’, adding: “Our findings showed that a city centre 20 mph intervention had little impact on long-term outcomes including road traffic collisions, casualties and speed, except for a reduction in traffic volume. Future 20 mph speed limit interventions should consider the fidelity [enforcement], context and scale of implementation.”
Certainly, it seems most experts are in agreement that collisions at 20mph are likely to result in better outcomes for all involved than those at 30mph or higher. So in that sense, driving at 20mph in urban and residential areas is a good thing.
But the jury is still out on whether it needs enforcement. 20mph schemes seem to show overall a minor reduction in average speeds, but the fact they are in areas where it is often congested too means many drivers average around 20mph anyway.
What is yet to be determined is if they are able to slow down those drivers who are causing accidents by driving too fast – those that speed in 30mph areas will probably speed in 20mph ones too.
Crucially though their overall top speed is likely to be lower as a result, and hopefully into the speed bracket where pedestrians have a much higher survival rate. Evidence for the success of this determine if 20mph becomes the default speed of all our urban roads.