Marc Brett wrote:
> On Fri, 01 Jun 2007 12:59:36 +0100, Matt B
> <"matt.bourke"@nospam.london.com> wrote:
>
>> Even studies looking at the more likely contributor to road danger,
>> "speed", such as the landmark Solomon (1964) study, tend to show that
>> speeds below, as well as speeds above, the mean for the road lead to an
>> increase in collision probability.
>
> Solomon's study was for US rural roads in the 1950s -- UK roads in the
> 21st century don't compare easily with those conditions. It had a small
> sample size, speed estimates were collected up to 3 years after the
> incident, and no account was taken for blood alcohol concentrations.
> Low speed incidents included cars turning to enter or exit the highway.
>
> At best, this study should be treated with caution.
Munden (1967) showed similar findings in the UK.
Harkey, Robertson, and Davis (1990) found the same so-called "U-shape"
relationship on urban roads. The sample was 532 vehicles involved in
crashes over 3 years, with alcohol and junctions excluded.
Fildes and Lee (1993) suggested that higher speed limits would result in
fewer crashes in some locations.
--
Matt B