Should there be a blanket 20mph speed limit around towns? Arguments for and against the proposal
Speed limits are a perennial hot topic, not just for drivers but for cyclists and pedestrians as well.
The current urban limit of 30mph has been in place for almost 90 years but recent years have seen growing demand for it to be reassessed, with some local councils taking their own steps to introduce 20mph limits in the name of safety.
Richard Cuerden, a director of think tank TRL (formerly the Transport Research Laboratory) recently reignited the debate, claiming that the current attitude around 30mph zones is outdated.
He told the Sunday Times: “Current guidance and regulation around 30mph default roads is completely out of date: we need to be thinking about 20mph.
“Until recently we talked about traffic accidents and accepted that people were killed or injured on our roads as a consequence of going about their daily life. It is not acceptable to us any more.”
Much of the argument around 20mph zones focuses on the impact on pedestrians. Various studies have concluded that a pedestrian hit by a car travelling at 20mph has a 90 to 97.5 per cent chance of survival, compared with between 50 and 80 per cent at 30mph.
Wales is piloting 20mph limits in eight areas ahead of plans to introduce a nationwide 20mph limit in towns and villages, citing a desire to improve safety. A growing number of local authorities are taking similar measures at a regional level but campaigners want the approach to be applied across the UK.
Campaign group 20’s Plenty says that a 30mph limit is “not fit for purpose for urban or village streets” and puts lives at risk. It argues that a flat 20mph limit is simpler and safer than introducing lower limits only at perceived high-risk areas and can help improve safety away from these hot spots.
Its founder and campaign director, Rod King, says: “The increasing evidence from local authorities who have already implemented wide area 20mph limits shows clear benefits on casualty reduction.
“There really can be little argument against 20mph as the limit for most urban and village roads. Local and national government should stop kicking the can down the road on replacing an 80-year-old 30mph limit, that never had any scientific basis, with one appropriate for the 21st century.”
Neil Worth of safety charity GEM Motoring Assist also believes that a blanket switch to 20mph zones is necessary to improve safety.
He says: “Low speed on roads can help save lives and are the heart of any community. 20mph speed limits where people and traffic mix make for streets that are healthy, green and liveable.”
He pointed to a study from Bristol which showed that the introduction of 20mph limits was associated with a 63 per cent reduction in fatal injuries between 2008 and 2016.
More recent data from Edinburgh also showed that collisions fell by a third in the two years after speed limits were dropped from 30mph to 20mph in the city centre.
However, a 2018 report from the Department for Transport (DfT) found there was “not enough evidence to conclude that that there has been a significant change in collisions and casualties following the introduction of 20mph limits in residential areas”.
And research by Queen’s University, Belfast, found that while there was clear evidence 20mph zones with traffic calming measures reduced the frequency and severity of collisions and casualties, there was a lack of evidence on the effectiveness of 20mph limits enforced only by signage - the likely means of implementing a blanket change.
Despite the mixed effectiveness, public support is growing for a nationwide drop in limits from 30mph to 20mph.
Research by IAM Roadsmart found 44 per cent of drivers supported replacing all current 30mph limits with 20mph, up from 30 per cent in 2014.
However, the organisation cautions against a flat 20mph limit.
Its director of policy and research, Neil Greig, says: “Improving road safety is key but a blanket ban on reducing 30mph speed limits to 20mph speed limits isn’t necessarily the best route.
“Each situation needs to be decided on a case-by-case basis, with local considerations and consultation playing an important role.”
His colleague Rebecca Ashton, head of policy and research, adds: “Different roads need different approaches, just changing the speed limit is not enough on its own.
“To have a positive impact on driver behaviour drivers need to understand why and see a difference in the road to get them to drive differently - changes in road layout, safety measures such as traffic calming measures - all of these help a driver understand why they need to reduce their speed in certain areas.”
AA president Edmund King believes that a 20mph limit around busy areas such as schools, and residential streets is the correct move but warns against a blanket 20mph limit.
He says: “Speed kills. No one denies this and we certainly welcome efforts to achieve zero road deaths by the end of the decade.
“However, setting 20mph as the default speed limit in all residential and urban centres could be a policy that backfires.
“We believe the strength in 20mph limits comes from targeting them where they are most needed such as close to schools, parks, and residential areas with high levels of walking and cycling.
“Here, 20mph makes complete sense and we would much rather this become the norm rather than the exception.”
However, he warns that a blanket doesn’t take into account the varying character of urban roads.
“While 20mph works in certain areas with local support, we still need some roads for movement for through traffic, buses, deliveries and here the speed limit should be higher.
“The best policy is to target the most important areas and then drivers are more likely to comply with the speed limits if they understand the reason for the reduced limits.”
The latest call for change comes after government figures revealed shockingly low compliance with 20mph limits. DfT data shows that in free-flowing traffic areas (without traffic calming measures), 87 per cent of cars exceeded the 20mph limit, suggesting even if there was a blanket ban, a significant change in driver attitude is needed.
However, the DfT report does point out that many 20mph limits include traffic calming, so some of the free-flow routes it monitors represent “through routes” rather than quieter residential streets.
Mr King adds: “Drivers need to take responsibility themselves and recognise very quickly that the best way to regulate speed is to control their right foot. It relies on all of us to remember the adage ‘it’s a limit, not a target’ whatever road we drive on.”