Across Australia, authorities are reducing speed limits to 40km/h in residential streets, school zones and in shopping thoroughfares. But should they be lower?
On the outskirts of Melbourne is the gorgeous coastal area of the Mornington Peninsula, a boot-shaped municipality of rolling land separating Port Phillip and Western Port bays.
Ocean views are mixed with open land for wineries, spas, golf courses and tourist attractions and, of course, the tighter-knit residential areas.
The population of more than 150,000 people uses local roads to ride bikes, walk or drive around town. So do the visiting tourists.
While it’s a wonderful place for a holiday, there have been problems with traffic on local roads. Prior to 2012, suburbs including Rosebud had “an alarming” number of pedestrians and bike riders involved in casualty crashes in residential areas and on local rural roads.
It led to the Mornington Safer Speeds project, supported by funding from the Victorian Traffic Accident Commission and VicRoads, including speed-reduction trials being established in the area.
Doug Bradbrook is a Traffic & Road Safety Strategist with Mornington Peninsula Shire and has recently overseen the assessment of the trials, which began in March 2012.
The trials were on two different types of streets, local roads in the residential area of the town of Rosebud, where the speed limit was reduced from 50km/h to 40km/h, and on rural roads, where the limits were reduced from 100km/h to 90km/h on some roads and from 90km/h to 80km/h on some other roads.
Despite a great number of local residents driving to work (more than 47,000 of the 150, 777 people drive to work according to Mornington Peninsula Shire’s community profile) the local community has embraced the speed reductions.
“In essence, community support is 80%,” Bradbrook reports, based on surveying Mornington residents before and after the trials. “It’s higher in rural areas, where 90% of people are in support of the moves.”
The council promoted, and residents now support, that “research indicating reducing speed limits by just 10km/h results in a significant reduction of serious and fatal crashes.”
It wasn’t just the attraction of fewer serious or fatal crashes that received support from local residents, it was also the fact they identified that slower speeds would mean more people walking, more kids and adults riding bikes in the neighbourhood and a closer community as a result.
“Across all groups the main reason for this support was that further reduced speed limits were thought to be more appropriate for children and the elderly,” Bradbrook said.
This perception of improved amenity from lighter traffic was first measured and confirmed by Donald Appleyard in his 1981 book Livable Streets. Appleyard, a professor of urban design, compared three residential streets in San Francisco that were very similar except that one experienced heavy amounts of traffic, one had medium traffic and the one had few vehicles using the street. It was his findings of variation in community connectivity that broke new ground. It showed there was another measure of the impact of traffic on human health, apart from the raw numbers of fatalities and serious injuries.
His studies found that residents of the street with low car traffic volume had three times more friends than those living on the street with high car traffic. A lightly trafficked street could contain neighbours that were close but a heavily trafficked street kept neighbours apart.
People stop cycling, and walking, to local destinations, such as local shops, schools and friends, as they do not feel safe or comfortable doing so
The other significant thing Appleyard identified was the extent of the home territory or neighbourhood that residents felt they belong to. In streets with heavy traffic, most people nominated that their neighbourhood was their apartment and not much more, often not even the rest of their building. These people said that theirs was not a friendly street, offering responses such as “No one offers to help each other”. On streets with little traffic, people felt their neighbourhood included multiple families in the street and the area extended for the length of their block on both sides of the street. An example response was “People are warm on this street. I don’t feel alone.”
These insights underpin the assertion from Bicycle Network that “Unless provision is made for quiet streets in residential areas, bike riding will remain an underutilised activity and transport.” The organisation points out while nearly all bike trips start on local residential streets, “the speed and volume of most local street do not suit most potential bike riders, especially children and family groups, as there are too many motor vehicles traveling too fast”.
The organisation is now running a campaign to convince state and local governments to move to 30km/h in selected local streets and precincts.
Its argument is that slower speeds in local streets mean more people will be happy to ride their bikes and walk, the flow on effect being that local suburbs will be healthier as people become more physically active, and socially active.
Bart Sbeghen, who coordinates the Healthy New Suburbs program for Bicycle Network, explains the link between high-speed traffic, reduced community and reduced bike riding.
“People stop cycling, and walking, to local destinations, such as local shops, schools and friends, as they do not feel safe or comfortable doing so,” says Sbeghen. “People also stop cycling and walking to other destinations as they do not have safe routes to get to surrounding areas.”
Sbeghen traces the roll-on effect, “Less confident people, including older people and children, stop riding and walking leaving only the more confident adults, leading to less diverse public spaces. People lose contact with their neighbours and make fewer friends.”
“All the above lead to less people using their public spaces and streets, which make them less welcoming to those who continue to use them. People feel less safe when alone, especially at night.”
Dr Alison Carver, a postdoctoral research fellow in the Centre for Physical Activity and Nutrition Research at Deakin University, has measured how lower speeds effect resident’s perception of liveability and specifically the scope for bike riding.
Her questions posed a theoretical reduction of speeds in residential streets to 30km/h, a speed that her research has shown is the best maximum for a liveable street.
“I found that 42 per cent of local residents (in inner Melbourne) said they would approve of 30km/h,” reports Carver. “I asked them about how they thought their behaviour would change regarding walking cycling and social interaction,” Dr Carver said.
“People were positive that they would walk and cycle more but the strongest findings were how they thought the behaviour of children would change.
“I found that 47 per cent of respondents agreed that more children would walk and cycle in their neighbourhood and 44 per cent agreed that more children would walk or cycle to school,” she added.
“Almost a third thought there would be more interaction on the local streets,” Carver continues. “That’s really important for mental health purposes and for building social capital, with people getting to know their neighbours. It also combats the stranger danger issue. If people actually know who’s in their neighbourhood then there’s more of a collective responsibility of adults in general who are looking out for kids on the street.”
While organisations and researchers look at liveability and health as reasons to reduce speed in local streets, roads authorities look to reduce speeds based on the numbers of serious injury and death caused by motor vehicle crashes each year. Many studies have shown lower vehicle speeds lead to fewer crashes and/or less serious consequences as a result. For roads authorities, and governments, fewer crashes seem to be their ultimate goal. As the NSW Road Traffic Authority website states: “Extensive research has shown that even modest reductions in travel speed will result in substantial reductions in the incidence and severity of road crashes.”
Jan Garrard, a part-time lecturer at Deakin University’s School of Health, writing in 2008 for the Safe Speed Interest Group, identified this approach as an old, reactive way of thinking and predicted a move to a more beneficial, proactive approach. “Traditionally, little consideration has been given to the additional, non-injury benefits of speed reduction,” she stated.
“These are multiple and wide-ranging, and are likely to include increased active transport and the associated benefits of active living and reduced motor vehicle use. If these ‘externalities’ were included in algorithms used for setting speed limits, it is likely that the benefits of speed reduction in urban areas would outweigh the disadvantages in the form of small increases in vehicular travel time and associated costs.”
Change in vehicular travel times was an aspect of the Mornington trial assessment, as a significant aspect to consider. However, it turned out not to be significant. While actual speeds in the residential streets did decrease following the reduction of the signed speed limit, travel times did not significantly change.
“Monash University Accident Research Centre found that there was no real impact on travel time,” says Bradbrook.
This is similar to the experience of the City of Melbourne, who also anticipated there would be no significant change in travel times following their introduction in late 2012 of a 40km/h limit on all streets within the central grid.
City of Melbourne is one of several leading proponents of speed reduction on local streets around Australia—other inner-city councils, such as Yarra and Port Phillip, have also led the charge. Yarra has 100 per cent of their local roads at 40km/h and has indicated that they would like to reduce speeds further to 30km/h.
Doug Bradbrook is pleased not only because Mornington is pioneering having reduced speed limits in Melbourne’s outer suburbs, but also because the trials are showing some great success.
The results are similar to those predicted by an independent transport consultancy.
“They found that overall, the safety benefits are expected to be positive,” says Bradbrook. “They predicted reductions in fatal crashes of 11 per cent in residential areas, 7 per cent on rural 80 km/h roads and 1.5 per cent on 90 km/h roads. Serious injury crashes are predicted to reduce in the range of 0.1 to 6 per cent across the residential and rural roads.”
For a convenient overview of Donald Appleyard’s Livable Streets research see Streetfilms 2010 film Fixing the great mistake.