SIR - According to statistics I read, speed camera convictions have risen very nearly threefold.

It follows, therefore, that one should expect a similar drop in crashes and accidents but this has not materialised, thus making your heading on "Speed: Cameras reducing crashes and casualties'" (T&A, December 5) incorrect and misleading in that they have, actually, shown only a small decrease.

The only factual thing is that revenue has increased in line with the numbers of additional cameras installed.

Speeding has not been proved to be the main cause of accidents. Bad driving is.

Philip Bird, Nab Wood Terrace, Shipley