"Billions spent, but fewer people are using public transportation," declares the Los Angeles Times. The headline might have been more accurate if it read, "Billions spent, so therefore fewer are using public transit," as the billions were spent on the wrong things.

The L.A. Times article focuses on Los Angeles' Metropolitan Transportation Authority (Metro), though the same story could be written for many other cities. In Los Angeles, ridership peaked in 1985, fell to 1995, then grew again, and now is falling again. Unmentioned in the story, 1985 is just before Los Angeles transit shifted emphasis from providing low-cost bus service to building expensive rail lines, while 1995 is just before an NAACP lawsuit led to a court order to restore bus service lost since 1985 for ten years.

The situation is actually worse than the numbers shown in the article, which are "unlinked trips." If you take a bus, then transfer to another bus or train, you've taken two unlinked trips. Before building rail, more people could get to their destinations in one bus trip; after building rail, many bus lines were rerouted to funnel people to the rail lines. According to California transit expert Tom Rubin, survey data indicate that there were an average of 1.66 unlinked trips per trip in 1985, while today the average is closer to 2.20. That means today's unlinked trip numbers must be reduced by nearly 25 percent to fairly compare them with 1985 numbers.

Transit ridership is very sensitive to transit vehicle revenue miles. Metro's predecessor, the Southern California Rapid Transit District, ran buses for 92.6 million revenue miles in 1985. By 1995, to help pay for rail cost overruns, this had fallen to 78.9 million. Thanks to the court order in the NAACP case, this climbed back up to 92.9 million in 2006. But after the court order lapsed, it declined to 75.7 million in 2014. The riders gained on the multi-billion-dollar rail lines don't come close to making up for this loss in bus service.

The transit agency offers all kinds of excuses for its problems. Just wait until it finishes a "complete buildout" of the rail system, says general manager Phil Washington, a process (the Times observes) that could take decades. In other words, don't criticize us until we have spent many more billions of your dollars. Besides, agency officials say wistfully, just wait until traffic congestion worsens, gas prices rise, everyone is living in transit-oriented developments, and transit vehicles are hauled by sparkly unicorns.

A more realistic assessment is provided by Brian Taylor, the director of UCLA's Institute of Transportation Studies, who is quoted by the L.A. Times saying, "Lots of resources are being put into a few high-profile lines that often carry a smaller number of riders compared to bus routes."

Los Angeles ridership trends are not unusual: transit agencies building expensive rail infrastructure often can't afford to keep running the buses that carry the bulk of their riders, so ridership declines.

• Ridership in Houston peaked at 102.5 million trips in 2006, falling to 85.9 million in 2014 thanks to cuts in bus service necessitated by the high cost of light rail;
• Despite huge job growth, Washington ridership peaked at 494.2 million in 2009 and has since fallen to 470.4 million due at least in part to Metro's inability to maintain the rail lines;
• Atlanta ridership peaked at 170.0 million trips in 2000 and has since fallen nearly 20 percent to 137.5 million and per capita ridership has fallen by two thirds since 1985;
• San Francisco Bay Area ridership reached 490.9 million in 1982, but was only 457.0 million in 2014 as BART expansions forced cutbacks in bus service, a one-third decline in per capita ridership;
• Pittsburgh transit regularly carried more than 85 million riders per year in the 1980s but is now down to some 65 million;
• Austin transit carried 38 million riders in 2000, but after opening a rail line in 2010, ridership is now down to 34 million.

Even where ridership is increasing, it's decreasing. After building two light-rail lines, transit ridership in the Twin Cities has grown by 50 percent since 1990. However, bus ridership is declining and driving has grown faster than transit.

Transit in some cities was hurt by the 2008 financial crash. But in most cases, declines in ridership parallel declines in service. If transit agencies reduce bus service to pay for the high cost of the rail lines they want to build, transit riders and ridership will be hurt.

Whatever the service levels, transit just isn't that relevant anymore to anyone. As I've pointed out before, more than 95 percent of American workers live in a household with at least one car, and of the 4.5 percent who don't, less than half take transit to work, suggesting that transit isn't even relevant to most people who don't have cars. This will only get worse, of course, as self-driving cars change the urban landscape.

"It's not the dream of every bus rider to arrive in a bus that was on time, air conditioned and clean, where a seat was available," the L.A. Times quotes USC civil engineering professor James Moore as saying. "It's the dream of every bus rider to own a car. And as soon as they can afford one, that's the first purchase they'll make."

Cities that invest in expensive transit infrastructure are ignoring the reality that, long before that infrastructure is worn out, self-driving cars will replace most transit. The short-run issue is that transit agencies that spend billions on rail transit or bus-rapid transit with dedicated lanes are doing a disservice to their customers. The most important thing they should focus on instead is increasing bus revenue miles in corridors where they will do the most good.