A letter asked about audible speed warnings in cars. For the past 10 years I have been using a device made by NCS Systems (www.ncs-systems.com) called Speed Angel, which provides both audible (switchable) and visual warnings of any speeds above 30mph. Warnings are bleeps/flashes at one bleep per 10 mph, or alternatively can it be instantly programmed to any set speed where it will give an alternating audible warning as that speed is approached, then a solid sound as the speed is reached-very useful in average-speed zones. The LED visual indicator is easily seen peripherally, with no need to look directly at it.

The device is about the size of a box of matches, and requires only a tiny hole in the dash for the small control button. No electrical connections are needed to the speedometer. It senses the pulses by induction. The great advantage of this device is that I no longer have to takes my eyes off the road to monitor my speedometer. Current cost is £79, a bargain compared with the current cost of speeding tickets.