The rush hour-and-a-half

By Sheila Cook

Whether you live in a modern, fast moving city or a slow, rural hamlet - you'll probably spend as long getting to and from work every day. But how's that going to work when everyone in the world gets a car?

Do you travel for roughly the same amount of time each day? And is it, on average, one to one-and-a-half hours? If it is, your behaviour is in line with your innate "travel-time budget". That's the name given to the observation that human beings down the ages and across different countries and cultures seem to travel for a surprisingly fixed amount of time.

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It doesn't matter how we travel - whether it's on foot, by car or plane, the amount of time we spend getting from one place to another remains constant. So if travelling is a deep-rooted human characteristic and we have always done it, will we carry on?

An Israeli, Yacob Zahavi, first came up with the idea of the "travel-time budget" in the 1970s. He found that as societies develop economically, people stick to their subconscious travel-time budget but shift from low speed to higher speed means of transport, thereby covering ever greater distances within the same amount of time.

What may have been just an interesting observation about global economic progress 30 years ago becomes a pressing issue today for policy makers trying to influence our travelling habits in the face of the threat of global warming.

The crux of the concern is this - as the world develops and populations grow, the 60 to 90-minute return commute will become ever more of a drag on the world's scarce resources as people switch from walking to the car, bus or train.

Energy gobbled up

There is going to be an explosion in the total number of kilometres travelled, according to Dr Andreas Schafer, who has studied travel behaviour worldwide.

The commute in many developing countries is long, and on foot

"At the moment the world population travels about some 30 trillion passenger kilometres