Twenty is not plenty for Cambridgeshire Police

This article was published in 2012, in Newsletter 102.

Compare the following headlines:

Newspaper headlines about 20mph limit

You might be mistaken and think the former was from 2008 and the latter from 2012, but clearly the police in Cambridgeshire have not caught up with the national trend.

There is no doubt that laws can be difficult to enforce if there is very poor compliance, and that education and perhaps some minor engineering is needed for recent 20mph areas. Education should aim to change the attitudes of the majority. We’ve most definitely seen these changes with drink driving, and the compliance with 30mph speed limits in urban areas has been improving in recent years for similar social reasons.

Engineering for 20mph limits usually means using expensive measures such as speeds humps which are unpopular with many road users. Cheaper alternatives are painted lines and good signage. These could be better used.

Government guidance has recognised these factors with the most recent publications suggesting that the default speed for residential and shopping streets should be 20mph and without the requirement of traffic calming measures. This would, of course, still leave our major radial and ring roads at 30mph.

Officers reported that the roads are too dangerous to stop speeding motorists

Hence it is hard to see how the police in Cambridgeshire justify their entrenched attitude, with officers reporting to an area committee that the roads are too dangerous to stop speeding motorists. Has anyone done a proper cost-benefit analysis of 20mph areas in Cambridge? The suggestion was that 36 hours of police time had been wasted on non-enforcement of the 20mph limits in the central area. I wonder how many hours of police time are wasted in investigation of crashes where inappropriate speed is a significant factor?

In 2009 the ‘official’ cost of a serious injury in a crash was £178,000. In the central area of Cambridge, now restricted to 20mph, there were 14 such crashes involving a motor vehicle between 2005 and 2010. If sticking to 20 just reduced this number by one third we’d save over half a million pounds. If it helps to save anything like that amount surely 36 hours of police time is a good investment.

It is perhaps worth noting that the Parliamentary Select Committee on Transport has said: ‘a rule which is not enforced is a rule that is not observed’. In order not just to save money but to make Cambridge streets more pleasant places for all we should expect this law to be enforced.

Jim Chisholm