The NOW 100 speed limit changes in South Australia

Aligning speed limits towards a Safe System by consistent application of the rural default speed limit on more rural roads was identified as a priority action in the Road Safety Action Plan 2011 & 2012 under Towards Zero Together – South Australia’s Road Safety Strategy 2020.
DPTI identified 52 (864km) of State and council maintained roads with a 110km/h speed limit located within 100km of Adelaide and on the Yorke Peninsula, and assessed as appropriate to reduce to the 100km/h rural default speed limit, based on crash history and risk assessment, national standards and guidelines and DPTI operational instructions.
A public education campaign ‘Now 100’ was implemented to inform the public of the
reduction in the speed limit and the reasons for doing so. The campaign comprised media relations, print, radio and online advertising and ‘speed limit changed’ road signs. A three month enforcement grace period was observed by SA Police following the announcement prior to enforcement of the new speed limit.
Post campaign research found that the education campaign resulted in a high awareness (67%) of the speed limit changes, and 58% of those surveyed believed that lowering speed limits would reduce the severity of injury when a crash occurs.
Speed surveys conducted a year after the reduced speed limit revealed a drop in speeds while the crash data reveals an indicative reduction in casualty crashes following the change.