Will providing better transit be enough to cope with city growth?Posted: September 6, 2010
It might seem counter-intuitive, but you can’t increase public transport’s share of travel significantly unless you simultaneously do something about cars. Yet this simple relationship is usually ignored by governments and lobbyists alike.
Back on 23 August I looked at the question of how our cities could grow larger but still be liveable. Public transport has a vital role in meeting this challenge, but the task is daunting. Notwithstanding current overcrowding on the train system, public transport’s share of all motorised travel is only around 11% in Melbourne and a little higher in Sydney.
The standard recipe for increasing transit’s share of travel is to offer a better product. This is popularly thought of as more trains and more light rail (only occasionally more buses).
It usually involves providing some combination of greater route coverage, higher frequencies, longer operating hours, faster speeds, better connections, more information and higher levels of comfort and security.
Improving quality seems a self-evident solution. After all, the area of the city with the best public transport offering – the CBD – is also the area where public transport scores best against the car. For example, 43% of all motorised work trips to the inner city in Melbourne are made by public transport and this study suggests the figure for the CBD is probably upwards of 65%.
This strategy works – but only up to a point. Consider, for example, the Melbourne inner city municipality of Yarra. It has a pretty high standard of train and tram services, yet 86% of all motorised weekday travel by residents of Yarra is still made by car (or 74% when walking and cycling are also included).
The fact is a high standard of public transport provision is not enough by itself to drive really serious mode shift. The missing factor is suppressing the car. Public transport only has a high share of work travel to the CBD because factors like high levels of traffic congestion and high parking charges nullify the car’s inherent advantages.
This is a critical insight. It tells us that in almost all cases travellers who have the option of driving will only prefer public transport when (a) the level of public transport service is high, and in addition (b), the advantages of the car are neutralised. It means that policies directed at increasing public transport’s share of travel won’t be successful unless they also embrace ways of making car travel less attractive.
This should be intuitively obvious. Absent factors like congestion, cars are almost always faster and more convenient than public transport. They offer greater privacy, security and the ability to carry belongings. Even the marginal cost of a trip is usually perceived to be lower by car than by public transport.
In the case of the CBD, high levels of congestion and high parking costs derive from the very high density of activities in the central area, especially employment. But density is not an essential condition for suppressing car travel. Market changes like higher petrol prices can also make driving less competitive.
Or deliberate interventions like road pricing, tax increases and regulatory changes can increase the cost of operating a car relative to the cost of public transport. This is an important point because it means that even in a relatively low density city like Melbourne (at least by European standards), it is possible to suppress car travel intentionally and thereby increase public transport’s mode share.
Of course deliberately increasing the cost of car travel is politically fraught. There are virtually no policies at either State of Federal level in Australia aimed at increasing the cost of driving. Even the report of the Independent Public Inquiry into a Long Term Public Transport Plan for Sydney gives little prominence to road pricing, treating it primarily as a means of raising revenue rather than as an essential step in attracting patronage to transit.
Traffic congestion is therefore the default way that public transport demand is supported at present (not that policy-makers do this consciously). But it is a very inefficient way. Congestion is associated with higher emissions and petrol consumption and does not discriminate between the importance or value of trips.
It is also commonly (and usually implicitly) assumed that substantially higher future prices for petrol and/or carbon will suppress car travel and hence drive demand for public transport. However this is an uncertain strategy. We don’t, for example, know the timing or the extent of future price changes. As I’ve noted before, even a $40/tonne price on carbon will only increase the price of petrol by 10c/litre (the carbon price currently advocated by the Greens is around $25/tonne). Nor do we know how easily or quickly drivers will be able to switch to substitutes like more petrol-efficient cars or electric vehicles.
So other than in places like the CBD, something considerably more deliberate, like road pricing, will very probably be required to suppress the attractiveness of cars sufficiently to force really serious uptake of public transport.
The key message is that it is not enough simply to have a Public Transport policy. It must be accompanied by a Private Transport policy. And it can’t just be a roads policy – it has to address action on the range of factors that determine the relative attractiveness of cars as against other modes.