I could not tell if the look on the woman's face was disdain or pity. But either way she did not understand that I wanted to rent a small car, not a big one. 'Are you sure you don't want an upgrade, honey?' she said, eyeing me suspiciously 'The car you've booked is really small.'

She offered a bigger car at the same price, perhaps thinking I was angling for a deal. No, I told her, I genuinely don't like driving big cars. I can't see the point and they are hell to park. Give me something small and boxy, please. In the end she let me have my way but I think she was genuinely offended.

That was in Texas. But it's happened at rental car counters all over America. The concept that you actually prefer a little car to a tank-like SUV seems difficult to grasp. Invariably I get offered a bigger vehicle for the same price. When I turn down the deal I am usually spoken to in a tone of voice that suggests I must be an escaped village idiot. Or very poor.

It is just one example of Americans' fanatic relationship with their cars. As political observations go that is hardly astute or original. A bit like a visitor to England making the wide-eyed discovery that the natives' have a remarkable fondness for tea. But what is less well known is that America's obsession with the car, which goes so deep it is reflected in virtually every facet of socio-economic life, did not happen by accident. Much of it was by deliberate design.

Or to put it another way: it did not have to be like this.

In between the wars many American cities had fully functioning electric tram systems that shuttled millions of citizens from their homes to their jobs without the need for a private car. American cities were more compact, more walkable and had vibrant downtowns that were the centre of urban life.

Even in southern California, which is now seen as the ultimate creation of the automobile, railways and trams were a huge part of life. Los Angeles was served by the largest mass transit system in the nation, including 1,000 trains a day running on the Pacific Electric Railway's 760 miles of track.

But take a drive - and it will have to be a drive - through most major US cities today (and particularly LA) and you see a different world. Downtowns lie abandoned to office blocks, gridlock rules on city freeways that have destroyed old urban neighbourhoods and suburbia sprawls out across miles upon mile of territory that only a generation or two ago was rural farmland. The figures tell the story best.

Americans make one billion trips a day and just 1.9 percent of them are by mass transit. There are 220m cars in a country of 290m people. The average US family makes 10 car trips every day.

But this did not just happen. Big business and government helped plan it this way. Many of those electric tram lines ended up being bought by car firms, notably General Motors. Between 1936 and 1950 a holding company backed by GM, Firestone and Standard Oil bought 100 tram firms in 45 American cities. They were dismantled and replaced by GM buses: more inefficient, more likely to lead to congestion and, in the end, more profitable to GM. Many bus lines then failed, leaving consumers with no choice but to buy cars.

But it was not just 'conspiracy' by the big car firms. Urban planners of the 1940s and 1950s seemed possessed with a manic zeal to push the car at the expense of public transit. Their vision was a sprawling suburbia linked by huge, broad expressways. One of the most influential was Robert Moses, who is responsible for much of modern New York's sprawl. Though never elected to office he was probably the most powerful man in New York from the 1930s to the 1950s. He once declared 'Cities are for traffic' and planned to build a huge freeway through downtown Manhattan that would have levelled much of SoHo and Greenwich Village.

Just think of that. Some of the most culturally and financially valuable real estate in the world was scheduled for destruction just so car owners could get across Manhattan more quickly. Many other less famous (but no less vibrant) neighbourhoods across America were not so lucky.

The focus on the car was a tragedy of human planning. Nor is it ending. Though much has been written about the revitalisation of American downtowns in recent years, by far the more important socio-economic phenomenon is the growth of the exurbs. These are the suburbs of the suburbs and - believe it or not - or even more car dependant. They are so spread out, so distanced from city centres and so utterly car-centric that mass transit is inconceivable for them.

But they are also now in pain. The current American obsession is not Iraq, it is not NSA wiretapping or even the never-ending abortion debate. It is quite simply petrol prices. Americans are being squeezed at the pump, now paying more than $3 a gallon. That is still cheap by most European standards but the shock is palpable in America. It also undercuts the economic model of the exurbs, rendering commuting costs so painful that suddenly, at long last, living by the car alone is starting to become unattractive.

Thank God, I say. There is little political or cultural will in America to tackle the love of the car. But brutal economics might just achieve it. Whenever I see those petrol prices ticking higher I give a lonely little cheer. I keep it quiet of course. I'm already seen as nuts just for liking small cars.

paul.harris@observer.co.uk