Myth busters: 20mph speed limits

Some drivers are very cross about 20mph speed limits.

The idea that towns and cities are cleaner, safer for walking and cycling, and generally nicer places to spend time when car speeds are reduced rankles with those who'd prefer to prioritise driving. No surprise then that some resort to flimsy arguments in favour of the status quo. Here are three:

20mph speed limits force me to drive in a lower gear

This might be the case if you're driving a high-revving classic sports car, but if you're behind the wheel of a modern car you'll be able to comfortably maintain 20mph in third or even fourth gear. If you don't believe us, then watch our our video. We drove a little city car with a one-litre engine on 20mph-limited streets to see how it performed.

https://vimeo.com/824088719?share=copy

20mph limits mean I'll use more fuel

Reducing peak road speeds in areas where people live, work or play saves energy and cash. Research into typical stop/start urban traffic by Future Transport reveals fuel efficiency peaks with speed capped at 20mph. Drivers benefit from up to 10p per mile in fuel savings without trips taking longer. That's a 30 per cent saving in urban fuel costs.

In built-up towns and villages, the key factor in fuel consumption is the number of times you accelerate back up to the speed limit after slowing down or stopping - the higher the speed limit then the greater that acceleration influences fuel consumption.

Engineering consultants at Future Transport modelled the fuel efficiency in accelerating from stopped to between 5 and 40mph. For a typical urban drive cycle - with repeated acceleration and deceleration - fuel efficiency peaks at a top speed of 15-20mph.

To drive at 20mph I need to keep my eyes focussed on the speedo and that's not safe

If you're unable to maintain a particular speed without your eyes glued to the speedo, driving's not for you. One of the things learner drivers master early on is the ability to keep to a particular speed while occasionally glancing at the speedometer to check their speed hasn't crept up. It's a basic skill that's assessed by examiners as part of the driving test. After all, driving steadily at 20mph is no different from maintaining 30, 40 or 70mph.

The ethical choice

The ETA was established in 1990 as an ethical provider of green, reliable travel services. Over 30 years on, we continue to offer cycle insurance, breakdown cover and mobility scooter insurance while putting concern for the environment at the heart of all we do.

The Good Shopping Guide judges us to be the UK's most ethical provider.

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