i Deputy Editor's Letter: Variable speed limits won't impress Clarkson, but the theory is sound

  • @jonesrhodri


The Government’s proposal to introduce a 60mph speed limit on a 32-mile stretch of the M1 will draw a predictable response. Businesses and motoring groups will throw their arms up in horror, before claiming that the speed limit should actually be raised, so people can go quicker. Environmentalists will counter with claims that not enough is being done, and longer sections of motorway should be limited.

Variable speed limits are nothing new on Britain’s motorways. They have been widely used to reduce congestion since their introduction on the M42 in September 2006, but this is the first time they will be implemented in a bid to cut air pollution. Jeremy Clarkson won’t be impressed, but the theory is sound – most vehicles operate more efficiently when driving between 50-60mph. But when they are unable to move at much more than crawling pace, it doesn’t matter where the speed limit is set.

So it seems while pollution is given as the reason, the problem also lies with congestion. It may seem counter-intuitive but on an overcrowded road, reducing the overall limit will actually raise the average speed. And with less starting and stopping, fuel economies will rise, cutting pollution. And let’s not forget the added bonus of making the roads safer.

As we battle the dual problems of more vehicles on our roads and the high cost of fuel at the pumps, surely we should welcome anything which will make our journeys easier and cheaper. After all is said and done, a 10mph reduction in the speed limit for 32 miles will add less than five minutes to your journey time.


Twitter.com: @jonesrhodri