Will simply building more public transport seriously suppress car use?

The Prime Minister's enthusiasm for cities is welcome. Now he needs to come to grips with the painful reality of how ineffectual most of the fashionable urban policy prescriptions are.

Not much to cheer about here - mode share of motorised travel (passenger kms) 1945-2014 for five largest Australian cities, public transport vs private transport (source data: BITRE)

Malcolm Turnbull should take a look at the exhibit above; it shows that public transport's share of motorised travel in Australia'a five largest capital cities has been depressingly low for decades, while private travel (essentially cars) continues to dominate.

There've been some small blips but there's no dramatic improvement notwithstanding the well publicised drop in per capita driving and, just the other week, a report that over-eighties are now more likely to drive than millennials aged 18-24 years.

Quite simply, public transport isn't even coming close to winning the "fight" with the car. Back in 2002, Melbourne's strategic plan set a target of 20% mode share for public transport by 2020. There was a well-publicised patronage surge over 2006-09 due mainly to unprecedented CBD jobs growth, but mode share stabilised since then at just 11%.

Mode share

I noted recently that simply building more mega public transport projects won't, by itself, be enough to seriously improve public transport's mode share (see Will politicians ever do anything real about cars in cities?).

That proposition probably sounds counter-intuitive and demands further explanation. So consider the impact the following proposed major rail projects would have on car use if and when they're completed.

Sydney CBD and South East light rail: This 12 km line is estimated to cost $2.1 Billion however 75% of forecast patronage will come from existing bus users. It's anticipated existing motorists will account for only 17% of users (see Is Sydney's new light rail line about saving the planet?).

Doncaster Hill rail extension: The Victorian Government's feasibility study for the proposed $4 – 6 Billion rail line in middle suburban Melbourne concluded that 98% of forecast patronage on the line would be diverted from existing public transport services (see Would a rail line to Doncaster really get cars off the freeway?).

Rowville rail extension: The proposed 12 km rail extension to Rowville in outer suburban Melbourne is likely to cost something like $3 Billion but the Government's feasibility study found it would reduce the number of car trips on a typical weekday in 2046 by just 15,000; that's trivial in the context of the circa 12,000,000 trips Melburnians currently make by car each day.