Reducing residential speed limits from 50km/h to 30km/h would protect cyclists from danger and make riding less stressful without causing traffic delays for cars, according to new research from RMIT University.
The study, published in Cycling and Micromobility Research, rated traffic stress levels for every road in greater Melbourne and modelled the effect of lower speed limits on bicycle and car travel. Lead researcher Dr Afshin Jafari said reducing the speed limit to 30km/h across residential areas doubled the amount of bike travel on low-stress streets, creating a safer environment for children and less confident cyclists.
“Slowing traffic makes bicycle riding less stressful, encouraging more people to choose bikes as a safe and viable mode of transport,” Jafari said. The study found car travel was barely affected, as the 30km/h limit was only applied on local streets rather than busier roads designed to maximise traffic flow.
Dr Elliot Fishman, director of the Institute for Sensible Transport, who was not involved in the study, said cycling rates in Australia were low at about 2% of trips to work and had barely shifted in 20 years. He noted that in cities such as Sydney and Melbourne, huge numbers of short trips under 5km were made by car and were suitable for cycling. “The main reason people are choosing to make those trips by car rather than cycling is that they don’t feel safe riding a bike,” Fishman said.
Fishman highlighted that lowering speed limits saves lives, citing that a cyclist hit by a car at 50km/h has about a 1.5-in-10 chance of surviving, while at 30km/h it is a nine-in-10 chance. He stressed that design changes, such as modal filters to discourage rat-running, are also needed to slow traffic effectively.
The findings come as Victoria enacts a new speed limit law allowing councils to propose 30km/h limits in school zones and local streets. By 2030, transport is likely to overtake electricity as Australia's largest emitting sector, and increasing active travel like cycling is a priority in the government's transport roadmap.
