20mph zones reduce accidents by an average of 60% (TRL report 215, 1996). In London a review of 78 sites found that they reduced injury accidents by about 42% and fatal or serious accidents by 53%.
On average, for every 1mph speed reduction, there is a 6.2% accident reduction.
A pedestrian hit by a car, travelling at a lower speed is much more likely to survive.
If a child runs out three car lengths ahead, when you are travelling at 20mph, you should just be able to stop in time. But at 30mph, you will hit the child, with a significant chance of injuring or killing them.
|45% of pedestrians are killed||5% of pedestrians are killed|
There is a significant difference between the characteristics of a 20mph speed limit and a 20mph zone.
There are four main techniques to traffic calming programmes:
Thames Valley Police have a commitment to enforcing the law and therefore, will be enforcing all speed limits.
To add the financial context, the cost to society of injuring different types of casualties is summarised in the table below. As well as the council’s commitment to make Slough’s roads safer for all, this valuation also lends weight to the importance of addressing locations where there is a clear need to protect vulnerable road users.
|Casualty type||Average value of prevention|
Department for Transport, Transport Analysis Guidance (TAG)
Accident data is publicly available at www.crashmap.co.uk.