Switching 50km/h speed limits to 30km/h would protect cyclists while barely affecting commutes, research finds | Cycling

Reducing residential speed limits from 50 km/h to 30 km/h would protect cyclists from harm and make driving less stressful while not causing traffic delays for cars, a new study suggests.

Researchers from RMIT University assessed traffic stress levels on each road in greater Melbourne and modeled the effect of lower speed limits on cycling and car travel.

Reducing the speed limit to 30 km/h in residential areas doubled the number of bicycle trips on low-stress streets, creating a safer environment for children and less confident cyclists, said the study’s lead researcher, Dr. Afshin Jafari.

“Slowing traffic makes cycling less stressful, encouraging more people to choose cycling as a safe and viable mode of transportation,” Jafari said.

Many existing cycle paths – narrow paths on 60 km/h roads – were very stressful for cyclists, which is one of the main reasons people choose not to ride, he said.

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Meanwhile, the study – published in Cycling and Micromobility Research – found that car travel was barely affected by the 30km/h limit because it was only enforced on local streets rather than on busier routes – such as main roads or motorways – which were designed to maximize traffic flow.

The findings come as Victoria enacts a new speed limit law allowing councils to propose 30km/h limits in school zones and local streets.

Institute for Sensible Transport director Dr Elliot Fishman, who was not involved in the study, said Australia’s cycling rates were low – about 2 per cent of trips to work – and had barely changed over the past 20 years, despite ambitions from state and local governments.

In cities like Sydney and Melbourne, many short trips (less than 5 km) made by car were more suitable for cycling.

Every day, more than 6 million journeys under 5km were made in Greater Sydney, including more than 2 million under 2km. In Melbourne, more than half of non-work trips were for a “cycling distance” of less than 5 km.

“The number one reason people choose to make these trips by car rather than by bike is because they don’t feel safe riding a bike,” Fishman said.

Lowering the speed limit would save lives, he said, and is one of the main reasons why some countries – such as the Netherlands, where 28% of all trips are by bike – have adopted the 30 km/h standard on residential streets.

“If you’re hit by a car going 30 mph, you only have a 1.5 in 10 chance of surviving. If it’s going 30 mph, you have a 9 in 10 chance,” Fishman said.

But it wasn’t enough to put up a 30 mph sign, he said; design changes also needed to be made to slow traffic.

Fishman’s research showed that modal filters — which use traffic management tools and landscaping to discourage “rat-running,” the practice of taking shortcuts between traffic arteries through residential streets — were most effective at improving safety and cycling rates.

By 2030, transport is expected to overtake electricity to become Australia’s highest emitting sector, according to the Climate Change Authority. This is the only sector where emissions are increasing, according to government data.

Increasing the share of active travel such as walking and cycling is a priority action in the government’s transport roadmap.