The move to restrict 20mph speed limits is an illustration of how far politics has moved from evidence-based policy (Ministers consider curbs on councils’ use of 20mph speed limits, 30 July). Time was when a Conservative government would care about road casualties. Back in the late 1980s, local authorities were set a government target of reducing casualties by 40% in five years through a combination of speed limits and physical measures. In York (and elsewhere), this was achieved by a hard slog of engineering design, extensive consultation and implementation. It was controversial, because too many motorists thought they drove without fault, but residents were fed up with challenges like crossing the road to go shopping and getting their children to school safely. We more than achieved the target of reducing casualties, and the use of 20mph speed limits was a crucial part of that. Thousands of people are fit and alive today because politicians were prepared to take brave decisions in the face of driver and media hostility. We also excluded traffic from 30 streets in the city centre to create a fantastic network of traffic-free streets that millions of tourists now enjoy every year. And the government author of these sensible accident-reduction policies? One Peter Bottomley MP, the transport minister at the time. Perhaps the prime minister could seek some wise advice from him. John Rigby Former director of environment, City of York council • In the late 1990s, I was the chair of highways and transportation in Lancashire county council. One morning, at a briefing with senior officers, I was told that Whitehall had just devolved the power to determine 20mph zones to local highway authorities. I was over the moon and totally enthusiastic. Road safety was an overriding priority at all times. I came up with our criteria off the top of my head. First, it was to be outside primary schools; next, the networks of terraced streets, of which there are many in Lancashire; and finally, residential estates. We were partway through the financial year so had to spend quickly. The individual 12 districts in Lancashire were in a better position than us to quickly identify these priority areas. So we asked them to submit competitive bids. Pendle district council was first in the queue. We started to get schemes in place very quickly, and devised a plan to cover the county over the next few years, making the appropriate budgetary provision. This remains one of the decisions I made in local politics that I am most proud of. Richard Toon Chorley, Lancashire • Department for Transport figures have shown that 86% of motorists drive at over 20mph in 20mph zones. I live on a road with a 20mph limit and can assure you that 86% is an underestimate. Drivers can get away with it because they constitute 35 million of the electorate. So what is the point of imposing curbs on a policy that is largely irrelevant? The sad answer is politics. The real villains are the advertising agencies that have spent a century locating the car at the centre of our lives – motorists are only driving in ways as shown in adverts. More generally, the advertising industry is probably just as guilty of generating the climate emergency as the much more maligned fossil fuel industries. Peter Taylor Tynemouth, North Tyneside • Have an opinion on anything you’ve read in the Guardian today? Please email us your letter and it will be considered for publication in our letters section.