Is 40km/h the new 50km/h? Why 10 km/h matters to WA streets

Could reducing the speed limit on local suburban streets from 50km/h to 40km/h save even more lives? That's the question explored in the latest episode of the Horizons by RAC podcast, where host Ruth Callaghan is joined by David Elston (RAC Manager Road Safety Policy) and Tim Judd (PJA Road Safety Engineer & Strategic Transport Planner).

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The discussion examines growing calls to introduce 40km/h speed limits on local residential streets across parts of Perth, following successful trials in areas including North Perth and broader road safety initiatives underway in Western Australia.

While a reduction of just 10km/h may seem minor, David explains why speed plays such a significant role in both crash avoidance and crash severity. Lower speeds reduce stopping distances, give drivers more time to react and dramatically improve the chances of surviving a collision, particularly for pedestrians and cyclists.

But the conversation extends beyond road safety alone. Tim outlines how slower residential streets can create more pleasant neighbourhoods, encouraging walking, cycling and outdoor activity while helping local streets feel safer and more connected.

The episode also explores community attitudes towards lower speed limits, lessons from previous speed reductions in WA, and how councils across Perth and around the world are approaching the challenge of balancing mobility with safety.

Listen now to hear the evidence behind safer speeds and why the debate over 40km/h residential streets is gaining momentum.

Podcast Chapters

(00:00) Introduction, WA's road safety problem and fatality statistics
(01:16) Guest introductions, Tim Judd and David Elston
(02:00) City of Vincent as the first inner-city council to trial 40km/h
(02:40) COVID's unexpected role in extending the North Perth speed trial
(04:15) How speed reduction improves road safety
(06:00) Stopping distances compared, 50km/h vs 40km/h
(07:00) Kinetic energy explained, why speed has an outsized impact on survival
(07:40) Pedestrian survival rates at 50km/h vs 40km/h vs 30km/h
(09:10) Research into survivability across different crash types
(11:15) 10km/h speed reduction linked to 30% fewer deaths and serious injuries
(12:25) Benefits beyond safety, noise, amenity, and community liveability
(14:45) The piecemeal problem, why network-wide limits are more effective
(25:40) The Margaret River Safer Speeds trial explained
(29:05) Perth inner-city councils expected to adopt 40km/h permanently
(33:20) What success looks like, kids walking to school, al fresco dining, liveable streets