All over the country, cities from Seattle to St. Petersburg are planning or building light-rail lines that are wasteful and inefficient. Thanks to lobbying by government contractors and local politicians hungry for “free” federal dollars, more cost-effective alternatives are forgone in favor of expensive, low-capacity transit.

Proponents misleadingly call these light-rail lines “high-capacity transit.” In fact, the “light” in light rail refers not to weight, but capacity; light rail is, by definition, low-capacity transit.

Rail advocates don’t like to admit it, but buses can carry more people, more comfortably, and to more places, for far less money, than light rail.

Three-car light-rail trains that run in streets can hold up to 450 people, more than any bus. But most light-rail lines can only run about 20 trains per hour, whereas a single bus stop can serve 42 buses per hour. By staggering bus stops, a single street can serve more than 160 buses per hour.

With 40 seats and room for about 20 people standing, standard buses operating on city streets can move more than 10,000 people per hour, compared with 9,000 people on light-rail trains. Double-decker buses in use in Las Vegas and other cities can move up to 18,000 people per hour, far more than any light-rail line.

Buses operating on city streets can thus satisfy any level of demand from 40 to 18,000 people per hour with low incremental costs to increase from one level to another. Rails, however, are enormously expensive: where a double-decker bus costs about $650,000, a single light-rail car costs $4.5 million and light-rail tracks cost well over $50 million per mile to install and even more to maintain.

A much higher share of bus riders get to enjoy comfortable seats rather than cling desperately to straphangers. Once buses leave city centers, they can fan out to many neighborhoods, while trains can go only where rails go, forcing most riders to switch to a bus or car to get to their actual destination.

When San Diego built America’s first modern light-rail line in 1981, it spent less than $10 million per mile (about $17 million in today’s dollars). This seemed affordable when compared with heavy rail (subways and elevated), which then cost more than $100 million per mile and today typically cost well over $200 million per mile.

Since 1981, however, light-rail costs have exploded: the least expensive light-rail line now under construction, in Salt Lake City, costs more than $50 million per mile, and the average is well over $100 million per mile. There is no way to justify these costs when buses are so much less expensive.

Even worse, some cities are paying heavy-rail prices for light-rail capacities, getting the worst of both. Honolulu is building an elevated line at a cost of $250 million per mile whose capacity will be little greater than light rail. Seattle is building an underground light-rail line for more than $600 million a mile that will be able to carry no more people than San Diego’s original, $17 million-per-mile line.

The high costs of building and maintaining light rail, which usually serves middle-class neighborhoods, often force transit agencies to cut bus service to low-income neighborhoods, making light rail as bad for transit riders as it is for taxpayers. It’s also bad for drivers since it often runs in streets and usually causes more congestion than is relieved by the few cars it takes off the road.

The willingness of many transit advocates to support such wasteful and expensive lines reveals they really don’t care about transportation. Rail manufacturers and contractors just want to make money. Urban planners use rail as an excuse to redevelop neighborhoods to higher densities.

For city officials, the incentive to build rail where buses would work better comes from a federal fund known as New Starts. This fund promises to cover at least half the costs of new transit lines, and cities that spend more get more. Thus, cities race to build the most expensive lines possible.

Though the feds may pay half the capital costs, local taxpayers have to pay not only the other half but the costs of long-term maintenance, which are much higher than bus costs.

The race to build light rail is a race to waste money. American transit agencies should abandon this race and stick to comfortable, affordable bus service.