Only 380,000 residents of Australia’s largest cities live in very walkable suburbs, all of them in the inner city. Creating new fringe suburbs with high walkability will be very challenging.

Sydney and Melbourne are by far Australia’s most walkable cities, according to US company Walk Score, which released walkability rankings of Australia’s largest cities last week. Adelaide scored third, with the company listing the CBD, Glenelg and Stepney as its most walkable suburbs.

Walkability is a term much-loved in planning circles. It summarises key urban qualities like density, design and diversity of uses. It extends the simple idea of compactness to also include connectedness and variety of destinations.

Sydney is the clear leader with an overall rating of 63 out of 100, followed by Melbourne with 57 and Adelaide with 53. Canberra’s at the bottom of the pile, with a score of just 40 – that puts it well behind the central counties of US “sprawl” cities like Phoenix (45), Dallas (47), Houston (50) and Atlanta (53).

Sydney has 29 suburbs defined by Walk Score as a “walker’s paradise” – ie they each score 90 or higher. Melbourne has 12 suburbs that meet the criteria and Brisbane five. Adelaide, Perth, Canberra and Newcastle only have one each.

The algorithm used by Walk Score essentially aggregates the number of amenities within walking distance of a point (eg an address). The amenities include “businesses, parks, theatres, schools and other common destinations”. More precisely:

It awards points based on the distance to the closest amenity in each category. If the closest amenity in a category is within .25 miles (or .4 km), we assign the maximum number of points. The number of points declines as the distance approaches 1 mile (or 1.6 km)—no points are awarded for amenities further than 1 mile.

The score at each point is weighted by the surrounding population density and then normalised to arrive at a suburban or city-level score.
It’s important to understand that the scores are approximations. They don’t take account of other factors that influence the desirability of walking in a particular city, like the steepness of hills, climate and crime risk.

Another limitation is the algorithm has no regard for the quality of proximate amenities – it weights them equally. A school is as important as a hardware store and a used car retailer. Further, it uses “as the crow flies” distances, not actual walk distances.

While they shouldn’t be taken too literally, especially at the level of specific addresses, Walk Score’s results are nevertheless consistent with what I would expect at the suburban and city levels.

They show the most walkable suburb in each city is Haymarket (Sydney), Carlton (Melbourne), Northbridge (Perth), Brisbane City, Canberra City, Newcastle City, and Adelaide City.

Taken together, the suburbs with 90+ walk scores in Australian cities house just 380,219 residents. They’re all located in the inner city, most of them close to the CBD. That has important implications for the policy objective of enhancing walkability across metropolitan areas.

Australia’s “walker’s paradise” suburbs are highly walkable because they enjoy a very special set of conditions not easily replicated elsewhere, including:

• An existing stock of historical higher-density housing mixed with former industrial, commercial and institutional buildings.
• Relatively high public transport density due to proximity to the focal point of the metropolitan radial public transport system
• Close proximity to the largest single concentration of jobs and consumer services in the metropolitan area
• A resident population, as well as a large number of daytime and night time visitors, with the wherewithal and the tastes to generate uses for non-residential buildings
• High levels of traffic congestion and high parking costs that reduce the advantages of car ownership

Walkability is more than density – it also has regard for destinations and the journey itself. Strategies to promote walkability in other parts of metropolitan areas must recognise that most of the conditions supporting the high walk scores of the inner city are special.

They would be difficult to reproduce in another place, suggesting that achieving high levels of walkability in other locations like new fringe suburbs is a challenging objective. It requires a different and more imaginative way of thinking.

This article was originally published on the Urbanist blog on Crikey.