Here's my top ten reasons why 20's plenty:
- Safety: there's no two ways about it, the biggest argument for 20mph is the increased safety for anyone out shopping, walking the dog, on their way to school, or even just getting out of a car. I dare you to read this and not think, yeah that could so easily have been me, and that kid could have been my kid. Every day five children and 20 adults are killed or seriously injured while walking or cycling on UK roads (Department for Transport, 2013). Lower speed limits reduce the severity of accidents. Whatever data you choose to look at, there is study after study showing that survival rates increase dramatically when speeds drop from 30mph.
- Reaction time: Stopping distances at 20mph are half that at 30mph, which means that you're more likely to be able to avoid hitting someone at 20mph, even if a child runs out, or a pedestrian slips and falls while crossing a road.
- Time: We're all busy people. Can we really afford to take it slow? Most city journeys on 20mph roads will only take a few seconds or minutes more. Living Streets research suggests that an urban journey of three miles, which would take 30 minutes in a 30 mph limit, only increased to 33 minutes in a 20 mph setting. That's a tiny price to pay for safer roads.
- Congestion: Slower speeds actually reduce congestion by smoothing out the bunching that occurs at higher speeds, so we should see some reduction in congestion.
- Pollution: 20mph should also reduce most forms of air pollution in our cities 30 km/h zones reduce CO2 emissions by 15%, NOX emissions by 40% and CO emissions by 45%. Only hydrocarbons will increase, by 4%. And bonus - cars should also be more fuel efficient.
- Noise: Reducing traffic speeds by 10 km/h, a noise reduction of 2-3 dB is achieved.
- Good for business: All of those things mean that 20mph zones are also good for business, making shopping, chatting, and socialising more pleasant and more common.
- Fairness: At present there are 20mph zones in lots of residential areas - especially our leafier suburbs - but this would make streets that are densely populated by families, students and the elderly safer.
- Happier mornings: In 20mph zones, more parents are happy to let their kids walk or cycle to school, which means fewer cars on the school run, which has got to make life saner for all of us.
- Demand: Surveys (scientifically conducted ones) repeatedly show high levels of support for 20mph. The 2011 British Attitudes Survey showed that well over two-thirds of us, including motorists, would like a 20mph speed limit in the streets where we live. As I've already reported, 60% of the people surveyed in the Edinburgh People's Survey in 2012 supported further extension of 20mph in the city centre and busy streets, and only 5% opposed it.
I've not footnoted everything. I do enough of that at work. The stats I have cited - and more - are to be found here. Happy reading: