20mph is good for everyone

20mph is good for everyone

By Alison Hill

Speed kills. The risks of injury and death when a cyclist or pedestrian is hit by a vehicle increases the faster the vehicle is travelling. A pedestrian hit at 40mph has a 31% chance of being of being killed; at 30mph that risk goes down to 7%: and at 20mph the risk is very low. One of the simplest and easiest ways to reduce injury to people who walk and cycle is to reduce the speed limit to 20mph. 

Research from the UK and worldwide shows that introducing 20mph zones reduces casualty rates, particularly amongst children. That is a compelling reason for introducing 20mph speed limits and zones. But there are also many other reasons why it is important to reduce the speed limit.  

Where speeds are low, streets are much pleasanter places to be in. In a low-speed environment people feel much safer and are more likely to walk and cycle. What is more vehicles going at lower speeds are less polluting resulting in better air quality in streets. People are therefore more likely to linger in those streets, which creates a better sense of place in these streets. And it is particularly important to have 20mph around streets with schools in them, where there will be lots of children cycling and walking.

With COP26 starting this weekend it’s also important to note that recent research showed lower speeds result in lower CO2 emissions as well as NOx (Nitrogen Oxide), because it is the acceleration of vehicles that is the greatest cause of emissions. Going from 30mph to 20mph reduces emissions by a quarter. Every little contribution to reducing CO2 helps. 

20mph can be good for drivers too. The evidence is that 20mph on residential roads doesn’t significantly alter trip times or inconvenience drivers, as constant 30mph is rare in built up areas due to junctions. Often going at 30mph just means an extra wait at the next traffic lights. Fuel consumption is lower so saves money. And travelling at a slower speed is less stressful! 

20mph should be the standard speed limit for all built up areas. Oxford was ahead of the game and in 2009 was one of the earliest cities to adopt 20mph in residential streets, while keeping the speed limit on arterial roads at 30mph.  (However, one of the disadvantages of introducing 20mph in residential streets and not arterial roads was the huge number of street signs. As the Oxford Mail reported in August 2009 1,900 new street signs were installed on the side roads along arterial roads.)  

We are delighted that at the Oxfordshire County Council Cabinet meeting on 19th October, the cabinet agreed to a proposal to endorse a policy for the implementation of 20mph speed restrictions across Oxfordshire. The cabinet papers mention the overwhelming support by residents of the county for speed reductions in built-up areas. They are proposing a set of criteria to help decisions on whether streets should move to 20mph. 

To quote from the papers that went to the Cabinet: “Essentially 20mph will be the new 30mph”. Signage will be the main way of implementing this policy though we know that traffic calming schemes are much more effective at reducing speeds. Enforcement is of course a problem given the limited resources that the police have to do regular speed checks.   

Introducing 20mph across the whole of the city, and all built up areas in towns and villages in Oxfordshire will make our streets pleasanter, healthier and happier places to be in, will bring down road injuries – particularly in children and people cycling and walking – will reduce pollution from NOx and carbon emissions, and in Oxford will remove large amounts of street signage making our streets look much less cluttered. What’s not to like?


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