Reducing residential speed limits from 50km/h to 30km/h would significantly protect cyclists and make riding less stressful, while barely affecting car travel times, according to new research from RMIT University.
The study, published in Cycling and Micromobility Research, modelled traffic stress levels for every road in greater Melbourne. It found that lowering speed limits 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.
Dr Afshin Jafari, the lead researcher, said slowing traffic makes bicycle riding less stressful, encouraging more people to choose bikes as a safe and viable mode of transport. He noted that many existing cycle routes on 60km/h roads are highly stressful, which is a main reason people choose not to ride.
The study found car travel was barely affected because the 30km/h limit would only apply on local streets, not on main roads or highways designed for traffic flow. The findings come as Victoria enacts a new law allowing councils to propose 30km/h limits in school zones and local streets.
Dr Elliot Fishman, director of the Institute for Sensible Transport, said cycling rates in Australia are low at about 2% of trips to work, and have barely shifted in 20 years. He highlighted that in cities like Sydney and Melbourne, millions of short trips under 5km are made by car but could be cycled. Lowering speed limits would save lives: a pedestrian hit at 50km/h has a 1.5-in-10 chance of survival, compared to nine-in-10 at 30km/h.
Fishman stressed that simply putting up 30km/h signs is not enough; design changes such as modal filters are needed to slow traffic effectively. Increasing active travel like cycling is a priority in the government's transport roadmap, as transport is set to become Australia's largest emitting sector by 2030.
