Year after year, road building authorities realign, widen, recurb, resurface, landscape, wall in or otherwise upgrade the region's streets and highways. At the same time, new roads are being constructed to reach farther out into the countryside or to improve access to developing suburbs.

Traveling around this expanding network and often stalled in bumper-to-bumper traffic slowed to a crawl by construction or accidents, I wonder where it all will end.

Are we really doing the right thing investing so many billions of dollars in paving so much of the landscape to accommodate the private automobile? Why aren't other modes of ground transportation being given equal treatment?

These questions came to mind recently as I moved slug-like along Interstate 95 one afternoon driving from Washington to Richmond, and again as I inched along Thanksgiving weekend from Cumberland, Md., back to the District.

Last month, I thought about transportation alternatives as I sat nearly motionless on I-295, alongside the Anacostia River, wishing at that moment to be traveling along the river by boat instead of by car.

In the District, the Whitehurst Freeway is about to get an overhaul and face lift costing tens of millions of dollars, all of which will do little to relieve traffic congestion.

Northwest of Washington, through Rockville and Gaithersburg, cars now can travel smoothly along I-270, channeled along multiple lanes as if in sluiceways lined by miles of concrete barriers. A decade in the making, widened I-270 probably will fill up and slow down again before the decade is over. Will it next be widened to 14 or perhaps 16 lanes?

Laissez-faire development, widely dispersed land uses of low density, still relatively cheap gasoline and the symbolic freedom of movement provided by private automobiles continue to be the dominant forces for road building.

But in the long run, even this freedom and flexibility, along with the apparent economies of car ownership and travel, may slip away or become illusory.

How free are we spending dozens of hours a month stuck in traffic jams? Will every American be able to afford his or her personal car as the costs of ownership, gasoline, insurance, maintenance and parking rise in the future? And what about the value of time consumed by protracted auto commuting?

How beneficial are limitless auto trips if the environments to which they provide access deteriorate? Globally, auto emissions, plus runoff from road surfaces, contribute significantly to degradation of air and water quality.

It could be otherwise.

Throughout the United States, there exists an extensive and underused network of railway rights-of-way and rail lines, an alternative armature for organizing urban growth patterns and intra-regional, intercity and commuter travel.

During the 19th and early 20th centuries, railroads stretched far and wide with their main lines, feeder lines and local spurs, many of which they still control but make little use of.

Railroad companies own not only hundreds of thousands of miles of rail lines, but also millions of acres of land adjacent to railroad rights-of-way that could be effectively developed.

Has the time come to seriously revive American passenger rail travel as an alternative to driving?

Intercity travel along busy, urbanized or urbanizing corridors -- in mid-Atlantic and Northeastern states, in the industrial Midwest and along the West Coast -- offers the best opportunities for exploiting the potential of comfortable, high-speed regional rail travel in the 21st century.

Anyone who has ridden Japan's famed "bullet train" or France's TGV (Train de Grande Vitesse) must wonder why America has nothing comparable.

Three years ago I rode the TGV from Paris to Lyon halfway across France, at speeds exceeding 150 mph with little noise or vibration, a trip of less than three hours that would have consumed as much or more time by airplane, including airport transfers. During the trip, I had breakfast, walked the length of the train several times and got a fair amount of reading done. Beyond the train's technology and the speed technology made possible, the experience was, above all, civilized.

Could rail travel in the United States ever match that in Europe and Japan for performance, cost and convenience?

How civilized -- and marketable -- it could be to travel between Richmond and Boston, New York and Chicago or Los Angeles and Seattle, at comparable speeds and with comparable amenity.

Likewise, would Americans not trade their automobiles for a quick, comfortable, economical commute by rail from a station near their home to a station near their workplace, reading the newspaper, talking and sipping coffee along the way?

Wouldn't many Americans consider vacationing by train, rather than by car, if civilized passenger trains would take them where they want to go? Using rail lines long in existence, why couldn't we resuscitate weekend or weeklong railroad excursions of yore, with trains going to favorite getaway places 100 or 200 miles from major American cities?

There are signs that a rail renaissance might be in the offing. Amtrak is very much alive. New light rail commuter lines, plus new commuter service using existing rail lines, are increasingly being considered, financed and put into operation, including here in the Washington area.

Of course, increased use of rail systems would not eliminate cars or the need for roads. People still would be dependent on automobiles for much of their local and regional travel since many trip origins and destinations are far from rail lines.

Nevertheless if rail travel became a reasonable alternative to driving for a substantial minority of the population, it could have a noticeable effect on chronic traffic congestion, which might subside to tolerable levels in many areas. Most important, transportation investment could shift from streets and highways to rail transit.

However, changing our transportation behavior and investment practices also requires that we change our strategies and methods for regulating land use, since land use and transportation are interdependent and inseparable.

For a rail strategy to succeed, for shifts from car to train to become economically feasible, future development -- business and employment, housing, shopping, cultural and recreational facilities -- must be concentrated along and near railroad rights-of-way. Passengers must be able to walk or take a short, no-transfer bus or auto trip to and from rail stations.

None of this is new to those who long have advocated unifying land use, transportation and utilities planning on a regionwide, rather than local, scale.

Indeed, the regional plan for metropolitan Washington, the "Year 2000" plan -- also known as the "Wedges and Corridors" plan -- prepared in 1961 is predicated on such an integrated approach.

Even 30 years ago, planners intended for intense growth to occur at nodes along high-density transportation corridors containing both road and rail systems. Wedges of open space and very low density residential development were to be preserved between each of the radial corridors.

Unfortunately, densities rarely reached high enough levels, growth dispersed more widely than anticipated and automobiles proliferated more rapidly than either roads or rail systems. Longer commutes and worsening congestion inevitably resulted.

Yet today all may not be lost if both public and private initiatives -- and investments -- could be redirected. Railroading could make a comeback. And while it won't solve all of America's urban and regional transportation problems, it could make traveling much more enjoyable.

Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland.