Reducing the speed limit in residential streets to 30km/h would significantly boost cyclist safety without having a major impact on car trip times.
New modelling by RMIT University’s Centre for Urban Research showed bicycle riders’ exposure to roads with high levels of traffic stress dropped by 30 percent when the speed limit was reduced from the current 50km/h limit.
Study lead author Dr Afshin Jafari said researchers rated every road in Greater Melbourne, in response to the Victorian Government enacting a new speed limit law allowing local councils to propose 30km/h limits in school zones and local streets.
Dr Jafari said they found lowering residential speed limits to 30km/h more than doubled the proportion of an average bicycle trip on low stress streets and roads from just over one-third to more than two-thirds.
He said while driving at 30km/h may seem slow, the limit mostly applied to residential streets, so it had little impact on average car trips, while the modelling showed the average short local trip only increased by about one minute.
“Most trips should use residential streets only at the start and finish, so 30km/h rather than 50km/h on those short sections makes little difference.
“Slowing traffic makes bicycle riding less stressful, encouraging more people to choose bikes as a safe and viable mode of transport.”
Dr Jafari said lowering speed limits was a practical, low-cost way to improve cycling safety.
“Installing physical barriers on every local street would be ideal, but it’s expensive and slow,” he said.
“Slowing down vehicles is a cheap and effective way to improve safety while we wait for longer-term infrastructure upgrades.”
Dr Jafari said the 30km/h residential limits would also encourage motorists to use main roads, leading to quieter residential streets.
“This should also create safer streets for our kids.”
He said while bicycle riding was often seen as the domain of city commuters, outer suburbs stood to benefit the most from lower speed limits.
“Outer suburban streets often don’t even have footpaths, let alone other infrastructure to separate bicycle riders and pedestrians from motorists.”
Read the full study: Modelling the impact of lower speed limits on residential streets for cyclist level of traffic stress and car travel time in Greater Melbourne.
