According to Griffith University transport planning researcher Matthew Burke, cutting speeds from 50km/h on local streets would not only reduce road trauma, it would also curb obesity rates by encouraging more people to walk and cycle.
"A car can stop in 3m travelling at 30km/h," the couriermail.com.au quoted Burke, as saying.
"It would make walking safe for everyone, it would make cycling safe enough for grandmas. It would be a very easy thing to do ... for next to no money," the expert added.
Dr Burke said cutting neighbourhood speed limits to 30km/h would make walking or cycling to school safer for children.
"By reducing road speeds, you limit traffic danger," he said.
"I think it's a joke that we think we're doing kids a favour with a 40km/h safety zone around schools when best practice globally is for all local streets to be down at 30km/h."
Lowering the speed limit indirectly addresses parents' fear of stranger danger, Dr Burke said.