Speed limits are being reduced on eight rural Onkaparinga Hills roads to help reduce road trauma following ongoing concerns from residents about speeding and road safety in the region.
These concerns—combined with the roads’ curves, crests, intersections, concealed driveways and roadside hazards—prompted the City of Onkaparinga to undertake a review of the eight roads (details below).
Why reduce the speed limits?
Speed is the single greatest influence on the forces experienced by the human body in a crash, and therefore speed management is a key factor in a safe road network. Research shows even small decreases in travel speeds lead to significant reductions in crashes and trauma.
Lower speeds:
- allow road users more time to assess hazards and avoid a crash
- reduce both the reaction time and vehicle breaking distance
- make it less likely a driver will lose control
- reduce the impact forces in the event of a crash and the crash severity.
The risk of a casualty crash approximately doubles with each 5km/h increase in speed on a 60km/h speed limited road, or with each 10km/h increase in speed on higher speed rural roads. Small increases in travel time can therefore help save lives and prevent injury.
The SA Government’s Road Safety Strategy is ‘Toward Zero Together’. This strategy advises that reductions in the average travel speed across the network is the most effective and swift way to reduce road trauma and would produce significant and immediate road safety benefits.
Reducing speed to reduce road trauma in Onkaparinga Hills
The council’s review of the eight roads within Onkaparinga Hills found on many of the roads, the average speed of vehicles is lower—sometimes substantially—than the existing speed limit.
Therefore, lowering the speed limit would only have minimal impact on travel times while reducing the risk and severity of road trauma. The council’s assessments found lower speed limits would add as little as four seconds to your trip (if travelling along Easton Road), up to 25 seconds (if travelling on Potter or Upper Penneys Hill Road).
On this basis, and amid a devastating year on SA’s roads (including fatal crashes in Onkaparinga), the council wrote to the Department for Infrastructure and Transport (DIT)—responsible for setting SA’s speed limits—requesting they conduct their own speed limit assessment.
DIT has now approved speed limit reductions on the eight roads, with council installing new speed limit signs together with temporary yellow “Speed Limit Changed” signs—the latter to be removed after 60 days—in November.
Although the limit changes will be made, you can still ask a question or provide a comment until Sunday 12 November at council’s Your Say page, where you’ll also find a map and fact sheet about the changes.
New DIT approved speed limits
- Bains Rd (between Piggott Range Rd and Knox Drive) – 70km/h (currently 80km/h)
- Coxs Hill (between Panalatinga Rd and Emu Creek Lane) – 70km/h (currently 80km/h)
- Easton Rd (between Piggott Range Rd and Grants Gully Rd) – 70km/h (currently 80km/h)
- Education Rd (between Piggott Range Rd and Singer Drive) – 70km/h (currently 80km/h
- Oakridge Rd (between 260m and 720m east of Homestead Drive) – 50km/h (currently 80km/h)
- Oakridge Rd (between 720m east of Homestead Drive and Main Rd) – 60km/h (currently 80km/h)
- Piggott Range Rd (between Grants Gully Rd and Bains Rd) – 70km/h (currently 80km/h)
- Potter Rd (between Clarendon Rd and Grants Gully Rd) – 60km/h (currently 80km/h
- Upper Penneys Hill Rd (between Piggott Range Rd and Craigs Rd) – 60km/h (currently 80km/h)
Pictured
A screenshot of a Google Streetview perspective taken along a section of Piggott Range Road where the speed limit will be reduced.