"We will end the war on motorists," the Transport Secretary, Philip Hammond, declared when the coalition took office. "Motoring has got to get greener but the car is not going to go away."

In the literal sense, Hammond is correct. The car in one form or another is here to stay and his department currently bases all of its projections on the assumption that car use will grow for ever.

And yet the growth in the number of miles and trips each of us drives began to slow in the early to mid-1990s, during the dog days of the last Conservative government. This trend became even more pronounced in the early 2000s, and since 2005 – notably before the recession and recent fuel price spikes – car use started to decline. Britain has already seen what transport policy wonks call "peak car".

Source: IPPR, using data from the National Travel Survey

The transport guru Professor Phil Goodwin, of the University of the West of England, points out that other, once-dominant modes of transport, such as railways, have also enjoyed what at the time would have looked like unending growth and then suffered what in hindsight was an inevitable decline.

So why not the car?

The motoring lobby will argue that, even in the era of peak car, almost 80 per cent of journeys are taken using private rather than public transport. While this is true, and suggests that only a fool would wage war on the motorist, there has been a small but symbolic shift in favour of buses and trains.

But peak car is arguably less about us switching from the car to the bus or the train to get from A to B and more about changes in society and attitude.

Researchers have only a fragmented picture of why peak car is happening and it's our job to find out more. But one of its most interesting aspects is that young people are more responsible for the trend than other age groups.

Indeed, it seems fewer young people nowadays harbour the ambition to drive. Between 1992 and 2007, the proportion of 17-to-20-year-olds holding a driving licence fell from 48 per cent to 38 per cent and that of 21-to-29-year-olds from 75 per cent to 66 per cent (note this is a PDF – see page 27).

The costs of motoring are doubtless a factor. For instance, according to an AA study, the average annual cost of car insurance for a 17-to-22-year-old man is £2,457. But young people aren't simply swapping cars for buses or bikes; they are choosing to own and use other technology instead, such as smartphones and tablet computers.

Significantly, the use of these technologies while driving is not only against UK law, but also difficult. A recent survey of college students in Colorado (where sending messages from smartphones while driving is not illegal) found that while 75 per cent of users said they often used their phones while travelling by bus, train or as a passenger in a car, only 10 per cent of them said they did so while driving a car.

We need to know more about peak car. Cutting carbon emissions from transport will be easier to achieve if we're working with the grain of people's behaviour rather than against it. But more important still is the implied shift in the politics.

Even in the era of peak car, it seems like a stretch, but if driving were to go the way of trains and buses, then fighting or ending the war on motorists may in the end prove a lot less significant.

Andrew Pendleton is associate director at IPPR on climate change, transport and energy.