As an American, I would like to give Irish people a bit of advice: car-orientated sprawl will ruin the social fabric of your nation.

In the US, we have become so dependent on cars that, in designing our suburbs, we think first about the efficient movement of automobiles - it is cars first, people second.

Such dependence on the automobile, however, has brought all sorts of unintended consequences. Take Atlanta, for example. In the 1990s, it was held up as an American model, leading the country in terms of employment growth, house-building and highway construction.

Now scattered over an area larger than the state of Delaware, Atlanta is learning a hard lesson about the consequences of urban sprawl.

According to Donald Chen, director of Smart Growth in Washington DC, the region's workers face the longest average commuting time and some of the most congested freeways in the US, with the result that large corporations such as Hewlett-Packard have started to look elsewhere to locate new facilities because of "quality-of-life" concerns.

USA Today reported that residents of the 13-county Atlanta metropolitan area drove their cars - some three million of them - an estimated 115 million miles per day in 1999. That's equivalent to a trip from Earth to the Sun and part of the way back, and it's projected to grow to 158 million miles per day by 2025.

Atlanta thought it could build enough highways to accommodate growth based on the automobile. But it has found this type of growth to be unsustainable and dangerous.

Road accidents increase with sprawl. Approximately 120 people die every day on American roads, and the death rate is disproportionately high among young people.

In fact, road accidents are the leading cause of death among American teenagers - mainly because of their dependence on cars.

American suburbs rarely have adequate public transportation and most places worth going to must be driven to. A survey by the New York Times found that a young person growing up in suburban Bergen County, New Jersey, one of the 10 wealthiest counties in the US, is three times more likely to die before the age of 24 than a person growing up in Greenwich Village, in the heart of the city. The reason: automobile accidents.

Automobile accidents, long commutes, road rage, traffic and air pollution are just the tip of the iceberg. But from my perspective, one of the more troubling consequences of sprawl is its negative impact on the "social capital" of communities, as documented by Robert Putnam, of Harvard University, in his recent book, Bowling Alone: The Collapse and Revival of American Community.

Social capital is defined as the networks and interactions that inspire trust and reciprocity among citizens. We usually acquire this trust and willingness to go out of our way for others through day-today, face-to-face relationships with our neighbours and other people in our communities - for example, at local shops, pubs, restaurants, parks or churches or within community groups.

What Putnam's book demonstrates is that social capital in the US is clearly declining. Compared to 30 or 40 years ago, Americans are less likely to get involved politically, help out in their communities, attend church or get together with friends and neighbours. As a result, they are less likely to trust other people.

According to Putnam, US states with low social capital have more violent crime and are poor places to raise children. "States that score high on the Social Capital Index . . . are the same states where children flourish; where babies are born healthy and where teenagers tend not to become parents, drop out of school, get involved in violent crime or die prematurely through suicide or homicide."

Putnam finds the decline in social capital to have several causes. Chief among these are that people feel they have to work more to succeed and have to commute longer and longer distances. "The car and the commute are demonstrably bad for community life. In round numbers, the evidence suggests that each additional 10 minutes in daily commuting time cuts involvement in community affairs by 10 per cent - fewer public meetings attended, fewer committees chaired, fewer petitions signed, fewer church services attended, less volunteering, and so on."

Exhausted Americans turn inwards to the home and turn on the television. Instead of learning about their world and the people in it by participating in that world and talking to people in it, they learn from television. And we know what the world can look like through the distorted lens of that medium.

It is my contention that many of the causes for the decline of trust and social capital in America have to do with the way we fail to plan or design our communities. In most modern housing estates in the US, there is very little community spirit. Modern estates are just that - housing estates: they are made up of houses. If you want to shop, go to church or to a restaurant, pub, community centre, sports pitch or school, you have to travel by car.

Because of the ubiquitous automobile, many American planners have separated out the component parts of our communities, assuming that we can all go where we want to go by car. Often, there are few opportunities to meet neighbours face-to-face and actually talk to them. Indeed, many developers don't even bother to build footpaths now. Ireland is still in a position to prevent the development of more community-less communities. But this will require planners and politicians who value communities or village-type settings that are both pedestrian and public transport friendly. There should be much less emphasis on building roads and car use and much more emphasis on innovative forms of public transport and public spaces.

Housing estates should be built only after communities have been planned. Currently, housing estates are built first. Schools, shops, community centres, restaurants, playgrounds, green space, viable public transport and all the rest are thought about later.

In Galway, where I have lived since January, it is largely private developers, not planners, who determine the shape of the places where people live. Housing developers build and sell houses. They do not plan communities.

The degree to which the Irish housing estate appears ready to follow the American model was made apparent to me at the recent grand opening of a housing estate called Binn Bhan, off the new Western Distributor Road in Galway. What drew me to it was a glossy brochure that billed Binn Bhan as "a new community set in green open space minutes from the city".

Of course, the cover of the brochure had smiling couples and children running hand-in-hand along beaches and in what looked like wheatfields. Needless to say, I didn't find much of what the advertisement claimed or pictured. Undeterred, I visited one of the showhouses and asked the salesperson: "Where are the schools?" Answer: "Well, there is one about 300 yards as the crow flies."

I also asked where were the shops, the parks and the playing pitches. After being told something about the crow flying again, I asked if there was to be anything one could walk to. I was told - politely - "you will have to ask Galway Corporation".

The bottom line is that I hope Ireland decides to think about and plan for the type of communities people can feel proud of and connected to, and that reflect Irish values. You don't need to copy Boston or Berlin. But, if you aim for Boston, don't be surprised if you get Atlanta.

Kevin M. Leyden is an associate professor of political science at West Virginia University. He is currently a faculty fellow at NUI Galway, researching social capital and planning in Ireland. He can be contacted at kleyden@wvu.edu