Busy bus lines can lose a lot of time to traffic, but the same can happen at stops, where boarding passengers cram through the front door so they can pay the fare. How much time, exactly? The Los Angeles Metro did an experiment, and it turns out, they lose twice as much as necessary.

While few would call Los Angeles a transit utopia, the city has one of the busiest bus lines in North America, the 20/720 on Wilshire Boulevard.

Los Angeles Metro has been working to improve this corridor for years, including adding miles of bus lanes throughout the corridor. The agency is also building a subway line, which a lot of people will probably use.

But moving buses through the corridor quickly will take even more effort. When it comes to making it happen, Los Angeles is on to something.

In the first half of the video, you can see how long boarding takes at Wilshire and Vermont with passengers only allowed to board through the front door. The bus is stationary for 69 seconds. That’s a significant amount of time considering that the 20 and 720 (the rapid version of the 20) come every four minutes.

In the second half of the video, when all three doors are in use, you can see that the dwell time drops to 31 seconds. That’s less than half of the time it takes when just a single door is available. The ability to use all three doors for boarding (with fare prepayment available through TAP readers at the stop) brings dwell time way down.

That means less waiting around on a stopped bus, but it’s important for more than just that: a line’s dwell times have a huge impact on its throughput (how many buses can run along a line in a given time), and long dwell times contribute to bunching.

Some bus lines in Vancouver use articulated buses that open all three doors for boarding. Image by Steve Boland licensed under Creative Commons.

To draw an analogy, our Metro lines can handle 26 trains per hour. But imagine what would happen if it took five minutes to load a train at Metro Center. Suddenly the throughput would drop to 12 trains per hour.

Finding ways to cut dwell times means more buses that traverse the line and, of course, faster trips. A 50% time savings is huge, though admittedly, not every stop will see such a dramatic decrease because the delay gets worse with volume. But on the 720 rapid line, stops are approximately a half-mile apart, so the spacing is more like rail and boardings tend to be concentrated.

Los Angeles’ experiment is another way WMATA and local jurisdictions could help increase bus capacity and decrease transit trip times. Busy corridors like 16th Street and Georgia Avenue would be excellent places to move toward fare prepayment and all-door boarding.

We initially ran this post in 2015, but since it still makes a relevant point about speeding up bus service, we wanted to run it again!

Thumbnail: Image by Oran Viriyincy licensed under Creative Commons.