The Heart Foundation’s Healthy Active by Design website is a brilliant resource for all who are interested in safer streets for people and better health as a result of being active. Nearly 5 years ago it was reported that Perth Transport Planner Tim Judd presented a paper on how “Reducing the speed limit on Perth suburban streets to 30km/h would curtail crashes and fatalities — and without significant delays in travel times.”

This has been highlighted by Heart Foundation’s Healthy active by Design website as the Padbury Experiment.

The Padbury Experiment was conducted in the Perth suburb of Padbury to explore the impact of reducing the speed limit on residential roads from 50km/h to 30km/h. The goal of the experiment was to transform roads into streets and create a safer and more liveable community. The intervention was designed to be self-enforcing, using appropriate road and path widths, reducing forward visibility, and speed control devices to ensure that vehicles cannot travel at more than 30km/h.

The experiment found that reducing the speed limit to 30km/h had minimal impact on travel times and associated costs. The travel time assessment showed that there was less than one-minute travel time difference from Padbury to the freeway or train stations when travelling at 30km/h compared to travelling at 50km/h. Evidence suggests that real travel speeds on local streets are well below the nominal 50km/h limit, making the reduced speed limit more feasible.

There are eight main local distributor roads within the suburb of Padbury, with most residential roads classified as Access Roads. The proposal to reduce suitable roads to 30km/h within Padbury acknowledged the role and function of the local distributor roads, but recognized that the required posted speed limit did not have to be the standard 50km/h. Four roads were to be kept at a 50km/h limit as they connect to the higher order arterial road network, while all other roads were proposed to have a self-enforcing speed limit of 30km/h.

The Padbury project demonstrated that having a network of local suburban neighbourhood streets at 30km/h would have minimal effect on journey times but offer significant improvements in road safety and pedestrian amenity. The intervention would provide an important new strategy for achieving continued reductions in injury rates from road crashes in Australia.

To ensure that the reduced speed limit was self-enforcing, appropriate road and path widths were used, along with features that influence the speed at which people drive. Examples include edge markings that visually narrow the road, the close proximity of buildings to the road, street trees, on-street parking, and pedestrian refuges and activity. Local ‘cycle-friendly’ area traffic management devices were also considered, such as raised intersection thresholds, narrow carriageway widths with traversable medians, gateway features, buildouts, offset kerbside tree planting, as well as narrower intersection design utilizing tighter turning radii.

The Padbury Experiment is an example of how reducing the speed limit on residential roads can create safer and more liveable communities. By transforming roads back into streets, neighbourhoods become important places for walking, cycling, social interactions, and even playful exploration by local children. The evidence suggests that lower speed limits in residential streets provide an important new strategy for achieving continued reductions in injury rates from road crashes in Australia.

Many others have written about the benefits of 30km/hr streets and how people have myths that need busting. Check out Busted: 5 myths about 30km/h speed limits in Australia

I wonder how much more evidence needs to be demonstrated that 30km/hr needs wide implementation?