Are we set to commute even further?

Change in average journey-to-work travel distance by region (km). Data from BITRE

The Age says jobs in Melbourne are losing pace with sprawl – it cites a new study by BITRE which predicts “an increase in the average commuting distance” by 2026 and a rise in journeys to work involving a road distance of more than 30 kilometres.

If a rigorous, hard-nosed body like the Bureau of Transport, Infrastructure and Regional Economics is saying things are going to get worse in the future, it’s worth sitting up and taking notice, right? It’s true BITRE does say that, but it’s also true the media tends to err toward a sensational rather than a sober interpretation of any given facts. In this instance the story is a bit of a beat-up.

For a start, it’s hardly news that commuting distances could “increase” over a period of 15 years given the spectacular growth in population projected for Melbourne. What matters is the size of any increase – if it’s only a 1% increase over the entire period, that’s an infinitesimal 0.06% p.a. However if it’s (say) 15%, i.e. 1% p.a., that’s worth taking note of. However The Age is silent on this score.

BITRE doesn’t say anything about the size of the predicted increase either. There’s a good reason for that. BITRE’s study isn’t an authoritative prediction of future commute distances as implied by The Age’s story. It doesn’t make forecasts based on the latest data, using innovative modelling techniques and complex algorithms as one might expect. In fact the report isn’t even about the future! – it’s actually about historical population, employment and commuting patterns in Melbourne up to 2006.

The Age relies on what is in effect an ill-advised throwaway line by BITRE. The report states (p 333) that if the Victorian Government’s spatial projections of population and employment through to 2026 are realised, the likely commuting implications include….”an increase in journeys to work involving a road distance of more than 30 kilometres and an increase in the average commuting distance”. There’s no analysis or supporting information behind this assertion, so too much shouldn’t be made of it. The prominence given to it by The Age suggests BITRE should’ve thought a bit harder before including it in a report about the past and the present.

However what BITRE actually has analysed in-depth is the historical change in travel distances – and here the picture is if anything somewhat mixed. The report looks first at what’s happened over 2001-06 (see exhibit). That isn’t necessarily a guide to what will happen in 2026, but it shows how current patterns are trending. The picture it reveals isn’t one of rampant increases in commute distances but rather one of relative stability.

BITRE found the average commute in Melbourne increased from 14.7 to 14.8 km, or by just 100 metres over five years. That’s a 0.7% increase, or a miniscule 0.1% p.a. Surprisingly, the average commute increased proportionally less in the outer suburbs than in the inner city – in fact as the exhibit shows, the average commute shortened in absolute terms in the Outer South, Outer East and the Outer West.

This is the real news! It’s important because commute distances have historically increased significantly, while commute times have remained relatively stable. So reliable evidence that commute distances have stabilised, even for five years, is noteworthy. Read the rest of this entry »