In article ,
Martin wrote:

How do you know?

The report I read was based on the reduction of accidents in Dutch urban area
as a result of lowering speed limits.

Because (a) I am a (somewhat rusty) statistician and (b) I looked
at several of those reports including, if I recall, one about
Holland.

and what was the problem you identified?

Mainly the lack of any evidence that the changes were not simply the
displacement of accidents to elsewhere, but also poor evidence that
the rates quoted were both real and due to the change.


Regards,
Nick Maclaren.