IN his letter of March 8, Mr Kay makes a number of points supporting the introduction of 20mph speed limits.
In particular, he quoted a figure of a 42 per cent reduction over a 20-year period in the casualties occurring in areas of London controlled by such limits, implying that this reduction was a direct result of those limits.
Without doubting these figures, I suggest it is also advisable, as I suggested in my previous letter, to look at a wider picture when quoting statistics. For instance, a study of the official Department of Transport National Statistics shows that in 2010 (the latest year yet published) there were 208,648 recorded casualties, of which 1,850 were fatal.
That was a reduction of 17 per ceny on 2009, serious casualties were down by 8 per cent, while pedestrian casualties were down by 19 per cent. That was in just one year.
However, if we compare 2010 with the national average for 1994-1998, we find a reduction of 48 per cent in fatalities, 49 per cent in serious and 32 per cent in slight, while the number of children killed or seriously injured fell by 64 per cent (yes, that is correct, 64 per cent). A further factor to bear in mind is that between these periods, traffic increased by 13 per cent.
Such figures surely suggest that great care and analysis must be given before, at considerable expense, road humps, pinch points, narrowings, rumble strips, coloured surfaces, various signs, flashing lights, etc., are removed and replaced, again at considerable expense, with 20mph signs and zones.