The Regional Transportation Commission is making an expensive mistake in considering light rail as a possible solution to any of Las Vegas’ transportation problems. Here are four reasons why Las Vegas should not only not build light rail, but also shouldn’t spend a single cent studying it.

1. Light rail is low-capacity transit. The RTC has called light rail “high-capacity transit,” but that’s a misconception. The “light” in light rail doesn’t stand for weight; light-rail cars actually weigh more than heavy-rail cars. Instead, it stands for capacity. According to the American Public Transportation Association, light rail is, by definition, transit “with a light volume traffic capacity.”

Sure, a single light-rail train can hold 450 people, compared with a bus that can hold 100. But for safety reasons, light-rail tracks can support only about 20 trains per hour. By comparison, Portland runs as many as 160 buses per hour down city streets, while busways in Istanbul, Guangzhou and other cities around the world move as many as 360 buses per hour.

Do the math: Buses can move several times as many people per hour as light rail, and they can do it faster at a much lower cost. Denver recently opened a bus-rapid transit line that is twice as fast and cost far less than any of the region’s light-rail lines.

2. It flopped in Phoenix. Rail advocates claim light rail has been a great success in Phoenix. What they don’t tell you is that Phoenix has lost almost as many bus riders as it has gained light-rail riders. In 2008, the year before the Phoenix light-rail line opened, 3.3 percent of the region’s commuters took transit to work. By 2015, it was down to 2.5 percent, compared with 4.4 percent in Las Vegas.

Light-rail advocates also claim the Phoenix rail line has stimulated economic development. In fact, many of the developments they count were projects planned before the rail line opened but were never built. Today they are vacant lots, and the companies that planned them are out of business, while most of the money spent on developments that were actually built were on government or government-subsidized projects.

While rail transit in some cities may have influenced the location of developments, no light-rail line anywhere has ever boosted the overall growth of any region. Why should taxpayers spend billions of dollars to shift development from one set of property owners to another?

3. In 10 years, no one will be riding it. Transit ridership is declining nationwide thanks largely to competition from Uber, Lyft and other ride-hailing services. When those services start using driverless cars, they will not only be faster and more convenient than transit, they will also be less expensive.

When you can take an air-conditioned driverless car from your door to your destination for less than the cost of riding transit, why would anyone want to stand in the heat waiting for a light-rail train?

Ford has promised to be mass producing completely driverless cars — cars with no steering wheels or control pedals — for ride-sharing services by 2021. Apple, Google, Lyft, Tesla and Uber are among the more than three dozen companies racing to beat Ford to the market. No matter who wins the race, the losers will be cities that went heavily into debt building rail lines that few people will use.

4. The federal government has stopped funding it. Arguing that rail transit should “be funded by the localities that use and benefit from these localized projects,” the Trump administration has announced that it will no longer give grants to new rail transit construction.

In making this decision, the administration is doing both cities and transit riders a favor. Too many transit agencies have gone heavily into debt and been forced to make drastic cuts to bus service in order to get “their share” of federal dollars to build rail transit.

The Regional Transportation Commission should save taxpayers’ money by looking ahead to the real future of transportation. That future will involve affordable driverless cars and driverless buses, not expensive, low-capacity rail.