Last week your correspondent (SD, London) complained about a pinch point and speed humps and the effect they were having on his property. However, he did say they slowed the traffic. I'm sure you will acknowledge that speed limits, especially in residential areas, where there are pedestrians, schools, shops, hospitals etc. are a necessity. There has to be a way to ensure that such limits are kept. Often quoted is the driver who was "only doing 35mph in 30mph area" but it is never just one driver, and rarely just 35 mph. It's thousands of drivers every week who exceed these limits, many by a considerable margin. It is they who make traffic calming measures necessary. Could you suggest an affordable, effective remedy for this perennial problem that blights so many lives?