Road safety benefits of an accros-the-board 50km/h urban speed limit

Until 2001, each Australian jurisdiction had a default urban speed limit of 60 km/h.
However Australia?s high urban speed limits came under increasing scrutiny and
jurisdictions progressively introduced a default 50km/h speed limit for particular
categories of urban roads and streets.
These changes have been accompanied by an extensive number of evaluations, with
the common finding being that substantial crash savings accompanied the reduced
speed limit. However the full magnitude of crash savings depends upon a number of
interrelated factors, including: the proportion of the urban road network converted to
a 50km/h limit; the proportion of urban crashes accounted for by the streets and the
roads to be converted to a 50km/h limit; and the extent of compliance with the new
speed limits.
This paper takes the data for an urban area in an Australian jurisdiction to estimate
possible crash savings if an ?across-the-board? 50km/h speed limit were introduced
for all undivided streets and roads in urban areas currently posted at 60km/h. It also
discusses the subsequent impact on specific road user groups.