Thirty years ago, the burgeoning Brazilian metropolis of Curitiba was clogged with cars and choked on smog. Unlike most of his counterparts in the United States, Mayor Jaime Lerner realized that building more roads was not the answer. Upon taking office in 1971, Lerner’s first priority was converting city-center streets into pedestrian walkways. Today, nearly 50 of Curitiba’s downtown blocks are car-free, and automobile travel has decreased by 28 percent even as the city’s population tripled. High-rise, high-density apartment buildings line the downtown transit corridors, with retail shopping on the ground floors. The city boasts minimal traffic congestion and some of the lowest levels of air pollution in Brazil.

Curitiba didn’t rely on high-tech fixes like monorails or subways to solve its transit woes. Instead, it turned to the poor stepsister of public transportation—and created one of the most efficient and profitable bus systems in the world. Now, special dedicated lanes (or “busways”) keep buses from getting bogged down in the main traffic stream. Twenty stations and unlimited transfers allow riders to move easily from one line to another, and one fare takes them nearly anywhere in the metropolitan region. Per capita ridership approaches that of New York, the most transit-reliant city in the United States.

It’s hard to see a Curitiba-like future through the graffiti-covered windows and belching clouds of diesel smoke in most major American cities, but it could happen here. In fact, the humble bus may be our best chance to get commuters out of their cars, save fuel, reduce pollution, ease traffic congestion, and make cities more livable for everyone.

While it may lack the glamour of light rail, a comprehensive modern bus system is eminently achievable, even for a city of modest means. Because buses use existing streets rather than expensive dedicated tracks, adding a new route is as simple as creating an unobtrusive stop, hiring a driver, and assigning a bus. These advantages enabled the rapid early growth of the nation’s bus system (see “The Rise and Fall of the Bus,”), which by 1999 accounted for 62 percent of public-transit riders’ 9.1 billion trips. (Of the remainder, says the American Public Transportation Association, 27 percent were made on Amtrak or other heavy rail; 5 percent on commuter rail; 3 percent on light rail; and 2 percent on trolleys, in vanpools, and on ferries.)

Despite their widespread use and great promise, buses don’t get a lot of respect: “Loser cruiser” is just one of the unfortunate tags that stick to the municipal and intercity bus. The disdain, however, seems inversely proportional to whether one actually rides the bus. During a Los Angeles stop in the early days of the 2000 presidential campaign, for example, then-candidate George W. Bush listened to the complaints of a man who rode two buses to work every day. The man asked how Los Angeles’s public-transportation system could be improved. “My hope is that you will be able to find good enough work, so you’ll be able to afford a car,” Bush replied.

Bus riders, however, aren’t ready to give up: Many are lobbying for less-polluting buses, dedicated lanes that allow buses to move faster, and--most important--more-equitable funding. In Los Angeles, according to the Bus Riders Union, the county’s Metropolitan Transportation Authority spends 70 percent of its operating budget on the 6 percent of its passengers who ride light rail. Meanwhile, overcrowding of 140 percent is typical on MTA bus lines, but unknown on the light-rail routes that link middle-class suburbs to downtown.

In 1994, the Bus Riders Union filed a civil rights lawsuit charging the MTA with running a separate but unequal system that rewards the “primarily suburban and business district” rail system and punishes 94 percent of its passengers--350,000 bus riders. (Angeleno bus riders are 81 percent black, Latino, and Asian/Pacific Islander; 57 percent female; and 60 percent poor.) In 1996, to the surprise of many transit officials, the bus riders won. In the largest settlement in civil rights history, a consent decree ordered the MTA to spend more than $1 billion over ten years to improve its bus system. Five years later, the MTA is still trying to appeal the ruling.

In Montgomery, Alabama, where Rosa Parks refused to sit in the back of the bus, many cannot now afford to sit in the front: In 1998, service was cut in half while rates doubled. Many other transit authorities also try to balance their budgets on the backs of those least able to pay. Nationwide, 27 percent of all transit riders have household incomes below $15,000 (the figure zooms to 38 percent if you exclude New York City, where transit is widely used by people of all income levels). “Transit is too often viewed as an inefficient social-welfare program designed to accommodate the needs of the urban underclass,” found a 1996 study by the Richmond, Virginia, chamber of commerce. “In most jurisdictions, transit is thought to be a political liability.”

Minority communities are also fighting back against the siting of polluting transit depots in their neighborhoods, a form of environmental racism. In New York City, where six of seven diesel-bus facilities are located in communities of color on the northern end of Manhattan, West Harlem Environmental Action filed a federal complaint last year with the Department of Transportation. According to the group’s director, Peggy Shepard, the buses are “idling on our curbs, idling outside our schools, idling outside our public swimming pools.” Her organization also wants the city to increase air-quality monitoring and to replace diesel buses with those fueled by natural gas.

The bus’s major drawback, in fact, is its reliance on polluting diesel technology. More than 92 percent of U.S. buses are diesel powered; even new ones create as much smog as 50 cars, and spew as much soot as 279 cars. These tiny soot particles (also known as particulates) collect in the eyes and nose and worsen respiratory problems, especially in children, the elderly, asthmatics, and people with heart or lung disease.

Last January, the EPA issued new federal clean-air standards for diesel buses, which were challenged by the National Petrochemical and Refiners Association. As that legal battle continues, 13 states are working to impose diesel standards of their own. California has led the way with the country’s strictest emissions laws for buses: A drastic cut in diesel fuel’s sulfur content will be followed, in 2004, by a 75 percent particulate-emissions reduction. These regulations, to be phased in over the next decade, will affect 8,500 vehicles operated by 75 transit agencies.

A growing number of communities are taking the clean-air initiative one step further by switching to compressed natural gas, biodiesel, electric, or electric/gasoline hybrid models. According to the Electric Transit Vehicle Institute, battery-powered electric buses reduce pollution by more than 98 percent over exhaust-heavy diesels. As for hybrids, the institute notes that they are “as clean, if not cleaner, than similar buses operating on compressed natural gas.” Cleanest of all are buses powered by hydrogen fuel cells, which have proved very reliable in demonstration projects in Chicago, Washington, D.C., and other cities. Last October, the United Nations’ Global Environment Facility gave $60 million to supply 46 fuel-cell buses for six of the world’s smoggiest cities.

The clean-bus movement got under way in 1991 when Santa Barbara, California, began operating a pair of 22-foot, open-air electric buses. The quiet, emission-free marvels drew curious transit officials from cities across the country, including Chattanooga, Tennessee. At that time, Chattanooga’s downtown was a gridlocked mess, with overloaded parking lots and three jammed main streets. Although 65 percent of its city center was dedicated to cars, traffic inched along. Shoppers avoided the area, hurting business revitalization.

The Chattanooga Area Regional Transportation Authority (CARTA) had been developing plans for a free public-transit loop that could service satellite parking lots and keep traffic out of the downtown grid. The Santa Barbara experiment convinced CARTA that the shuttle buses should be battery-powered electrics. The long, flat floor of a transit bus makes a perfect platform for batteries, and the short downtown loop is easily made without recharging. (Electric-hybrid buses offer greatly extended range for cities where short loops are not practical.)

With $19.6 million in state and federal funds, CARTA purchased 16 electric buses in 1992 to serve three new parking garages. Chattanooga was soon operating the country’s largest electric-bus fleet, and the shuttle is now the primary transportation for downtown workers. Cyclists and pedestrians travel in over the Walnut Street Bridge, which once funneled cars into the city, but is now dedicated to nonmotorized use.

Chattanooga’s experiment was a success because the electric buses didn’t simply banish the tailpipe; they also reduced traffic. Like the dedicated busways in Curitiba, the best new transit systems get buses off the main thoroughfares. Busways offer the speed and gridlock-free commuting of light rail without the crippling construction costs or expensive equipment. Buses on dedicated routes can regularly travel at 35 miles per hour and adhere far more closely to schedules. And establishing a busway can be as easy (and cheap) as closing a lane to other traffic.

Another success story is Ottawa, Canada, which adopted its “Transitway” of dedicated bus routes way back in 1974. Because of this foresight, three-quarters of all peak-hour trips into downtown are now taken by bus, and a third of all regional jobs can be reached on foot from a bus station. The Transitway averages more riders per capita--265,000 a day--than any other system in North America, even though it was 30 percent cheaper to build and is 20 percent cheaper to operate than a light-rail system.

In the United States, dedicated busway development is just getting started: As of 1999, a mere 1,755 miles had been designated, with 135 more on the way. Back in the 1970s, Detroit briefly led American mass-transit with an ultimately ill-fated monorail. (The planned system of connecting lines was never built and the three-mile downtown loop is known as “the train to nowhere.”) Now the Motor City has a second chance to be in the vanguard with a planned busway that would speed up traffic with pre-boarding fare collection, fast loading and unloading from sheltered stations, and color-coded routes. The city envisions a three-tiered system that would include SpeedLink busways (touted as a “train on tires”); InterLink, a traditional bus system for longer trips; and HomeLink, a neighborhood-based “paratransit” network consisting of small vehicles that can be dispatched by telephone for trips to stores, schools, and medical facilities.

A variation on the busway is the “signal-priority” technology used by Los Angeles’s Metro Rapid, a natural-gas line that began limited service in June 2000. (Speeding up slow-moving transit buses is a particular concern in Southern California, where an afternoon bus ride from Santa Monica to Los Angeles that took 39 minutes in 1991 had doubled in duration by 2000.) Signal priority relies on antenna loops buried in the pavement that communicate with bus-mounted transmitters: A bus approaching a traffic signal triggers the light to remain green for an additional ten seconds.

To prevent bunching, buses arriving ahead of their scheduled time get no assistance from the signals. So far, signal priority has cut travel times by 25 percent and may be implemented on an additional 20 bus lines. An expansion to dedicated busways is also being considered.

In his little-known 1863 book, Paris in the Twentieth Century, Jules Verne imagined another city that had grown dramatically, but one with neighborhoods arrayed along new train tracks. The trains themselves had bid the Iron Age adieu; they were lightweight and ran on compressed air, so nearby residents suffered neither steam nor smoke.

“What would one of our ancestors have said upon seeing these boulevards lit as brightly as the sun,” Verne wrote, “these thousand carriages circulating noiselessly on the silent asphalt of the streets . . . these glittering trains, which seemed to furrow the air with fantastic speed?” The 21st century may yet prove that prescient writer’s vision true worldwide, with one key difference: Each one of those silent, glittering vehicles will be a bus.