I think we need to be wary of the contemporary push to “demonise” commuting for the time it consumes, as often a longer commute means more time on public transport.

Concern about long commutes is one reason the Victorian government is backing the goal of a 20-minute city as a key plank of the forthcoming strategic plan for Melbourne.

But in the nation with the highest level of car commuting in the world, the 2011 annual American Community Survey reveals a less worrying picture. The average one-way commute in the US isn’t the interminable slog on congested freeways the popular stereotype would have us believe. It’s 25.5 minutes.

Just over 40% of workers commute less than 20 minutes one way, and 64% commute less than 30 minutes. In fact, 85% of US commuters get to work within 45 minutes. Just 8.1% of workers have “long commutes”, defined as more than 60 minutes.

It’s all the more interesting because American workers like to travel by car. Of those who leave home to go to work, a whopping 90% travel by car, either as a driver or passenger. Only 5.3% commute by public transport and 4.8% walk, cycle or use other modes.

But those long commutes can often be blamed on public transport. Those who commute for more than an hour are more than four times as likely to use public transport as other commuters. This does not sound like a nation being fattened up by long commutes. Some 4.3% of the workforce are home-based. That figure rises to 8.3% when those who work from home at least one day a week are added Marissa Mayer, take note).

Unfortunately the data isn’t available at metropolitan level, but it’s likely very big cities — and especially the small number in the US with well-developed rail systems — have the longest commutes.

The proportion of people with commutes longer than an hour is over 10% in just seven states: California, Illinois, Maryland, Massachusetts, New Jersey, New York  and Washington DC.

Those seven states include all or parts of some of the largest urbanised areas in the US — i.e. Los Angeles, San Diego, San Francisco, Oakland, Chicago, Philadelphia, Baltimore, Washington DC, Boston and New York. A number of these also have extensive commuter rail systems.

The journey to work is one of the most critical trips we make. It shouldn’t be surprising we’’e prepared to travel longer for a better-paying job, a more secure job or, given the number of hours we spend at work, to get to one that’s more pleasant and rewarding.

Travellers are inclined to operate on a time budget. On average, they take advantage of an increase in speed to travel further within the same time envelope — to expand their job and/or residential options — rather than to shorten their commute.

We also need to recognise that public transport commutes take considerably longer on average than work journeys by car. In Melbourne, for example, the median commute by public transport takes almost twice as long as by car.

That means policies designed to increase public transport’s mode share will in many cases lead to longer commutes. The difference will be largest in conditions where driving speeds aren’t slowed severely by heavy congestion.