LOS ANGELES — The first segment of the Los Angeles Metro D Line extension opened, carrying riders from Koreatown to Beverly Hills. The full nine-mile extension is scheduled to be completed by the fall of 2027, ahead of the 2028 Summer Olympics, which will involve more than forty venues across the city.

The D Line runs east to west underneath Los Angeles roughly along the path of Wilshire Boulevard. For decades, the line existed as a stub of just two stops past its junction with the north-to-south B Line. Once finished, the extension will connect riders to many of the city's busiest destinations and complete the trip from Brentwood to downtown in about twenty-five minutes.

"There's nothing like this particular subway extension to really demonstrate that Metro has arrived." said Stephanie Wiggins, Chief Executive Officer of the Los Angeles County Metropolitan Transportation Authority. "We hope Angelenos begin to see that this city can be a transit-first city, and that Metro can be part of their life style."

Wilshire Boulevard runs nearly sixteen miles from downtown Los Angeles to the Pacific Ocean and is the densest urban corridor west of the Mississippi River. Every weekday, for three hours in the morning and three hours in the evening, the boulevard is gridlocked. During peak hours, it can take thirty minutes to cross a half-mile section to either side of the 405 freeway, and as long as an hour to travel the five miles from Westwood Boulevard to Fairfax Avenue. About four percent of Los Angeles residents regularly use public transit, compared with two and a half percent who walk.

The boulevard's origins trace to 1895, when Henry Gaylord Wilshire began developing a luxury residential community on the western edge of Los Angeles. He cut a strip of land four blocks long down the middle of the subdivision and donated it to the city for a grand boulevard, on the conditions that it be named after him and that rail lines be banned from the thoroughfare. The city wrote those conditions into municipal code.

At its peak in the 1920s, the Red Car network comprised more than a thousand miles of track, making it the largest rail-transit system in the United States. The Red Cars were the transportation of choice for all but the wealthiest Angelenos, and riding to the beach or into the San Gabriel Mountains was a common leisure activity. By 1961, the last operating Red Car line was decommissioned.

"People started to get tired of the long lines, how slow it was, and then they started to get stuck in traffic by cars." said Ethan Elkind, an author. Eric Avila, another author, attributed the decline to driver behavior and public indifference. "They were driving—they didn't care about public transit anymore." Avila said. "It was apathy on the part of Angelenos."

In 1985, an unventilated buildup of methane gas in the basement of a Ross department store caused an explosion that razed several city blocks and injured twenty-three people. Henry Waxman proposed a bill in Congress to ban the use of federal funds for tunneling under a large swath of Wilshire Boulevard, and the bill passed. The B Line was rerouted to avoid the methane zone by turning north from Wilshire Boulevard and heading up to Hollywood.