It was disappointing to see several myths and misunderstandings given an airing in response to the launch of the "20's Plenty" campaign in Altrincham. Lower speed limits are becoming the norm across many parts of the country, including most London boroughs, but our local councils are lagging behind.

The evidence from across Europe is that consistent lower speed limits, without speed bumps, reduce overall emissions. Gentler acceleration and braking by drivers proves to be the natural response, and quieter streets enable more journeys to be made on foot or by cycle instead. In British cities where 20mph limits have been put in place, average traffic speeds have dropped, without needing any additional enforcement or physical traffic calming.

Most roads that people live on were certainly not designed for the traffic they now handle. Many of the most concerning locations for road safety in Altrincham are where typical speeds are between 20mph and 30mph. Every 1mph reduction in speed reduces the risk of collisions by 6%.

One correspondent mentioned the 85th percentile "rule" in defence of existing speed limits. This is just an outdated, unscientific and flawed rule-of-thumb, with origins in suburban sprawl of 20th century America. Oil was cheap, roads were the future, and the car was king. Pedestrians and cyclists were ignored entirely.

We should instead be looking to examples such as Utrecht. There, developing a truly people-oriented and bike-friendly city centre now means that over half of all journeys are made by bicycle. 13 percent of households have felt able to opt out of car ownership entirely, over the past seven years alone.

Trafford Green Party fully supports the campaign in Altrincham, because of the potential improvements for environment, for safety, health and quality of life.

We encourage residents anywhere in Trafford to contact their local councillors to express support for the national "20's Plenty For Us" campaign, as it could eventually be rolled out to residential streets across the whole borough.

Trafford Council needs to stop hiding behind the promise of forthcoming studies and consultations, and take action to make our roads safer, cleaner and more pleasant for everyone, based on the evidence already available.

Owain Sutton

Altrincham