WHY is the Lancashire Partnership for Road Safety claiming that speed cameras are responsible for the fall in deaths on the county's roads (LET, September 28)?

Accidents, by definition, are unexpected events, not carried out with intent. How on earth can unexpected events from one period be compared with unexpected events from a previous period? Natural variability, with or without speed cameras, could produce much the same result.

Drivers with different levels of ability and varied states of mind use different roads on different days at different times in different weather conditions. The same is true of other road users, too.

Is there a constant in there somewhere to conclude that speed cameras are a success? I don't think so -- unless the partnership is claiming that all accidents are caused solely by speed!

Accidents varied up and down before cameras were introduced. Indeed, why has the partnership selected April-July as the period to show cameras are working? Different periods can be selected to show different things.

It's interesting to note that, in the past, other police forces have trumpeted that cameras have reduced accidents over their area.

Such claims were made even though the area comprised of many locations without cameras.

Then, shortly after, accidents increased. Around the same time, the press releases heralding cameras mysteriously dried up. One such force area's website still quotes a period during which accidents fell as proof of their cameras effectiveness.

However, they fail to mention the rise in fatalities for the following year, months after the apparently unhelpful data was leaked to the press.

So, wouldn't it be cheaper to put garden gnomes at the side of the road? If accident numbers subsequently fell, everyone might rest easier knowing that gnomes were beneficial to road safety. More gnomes could then be introduced to improve safety further.

Frankly, it is no more ridiculous than claiming that the unobjective enforcement of one offence is responsible for greatly reducing accidents.

SIMON TONKS, Kinnoir, Huntly, Aberdeenshire.