It used to be that Metro’s “next train” arrival signs only displayed trains that were coming within the next 20 minutes. Now, the signs list trains up to 40 minutes away. Reader Tom F. wrote in to ask why.

Arrival screens at Union Station. Photo by the author.

“On the weekend,” Tom wrote, “You might see trains spaced at 5 minutes, 35 minutes, and 40 minutes on the PIDS. Is this a quiet admission by WMATA that while weekend service is awful, people still have the right to know that the next train won’t be arriving for 38 minutes?”

Resident GGWash WMATA expert Stephen Repetski said that Tom is basically right:

“WMATA recently updated the software for reasons including weekend single-tracking whose headways were longer than that PIDS could show and would thus be blank when there really were trains coming (eventually). They now go out to 40 minutes, up from 20.”

According to a recent WMATA Board of Directors document, WMATA undertook the update for customer service reasons:

“We undertook this improvement after hearing from riders that it is helpful for late-night and weekend travelers who may experience longer waits because of service changes around rebuilding. We continue to develop solutions to more difficult challenges such as predicting trains in a single tracking area, or when a train is departing an end-of-line station, but hope this enhancement provides more detail when choosing to travel Metrorail.”

Stephen added that Brian Anderson, WMATA’s social media manager, told him the following:

“In regards to PIDS, the software that is behind PIDS is actually incredibly complex, taking data from thousands of sources and distilling it into the predictions you see on the platforms across 91 stations. Any change in code has implications that must be carefully considered to ensure that the system continues to work reliably.

“In building the case for an extended look at predictions on PIDS, some of us on the Digital team took note of negative rider feedback upon encountering blank PIDS, not because the PIDS were malfunctioning, but because the headway was winder than the 20-minute threshold. We took this feedback to the group responsible for PIDS with a suggestion that we try a 40-minute threshold instead. That kicked off the process of internal meetings to get everyone on-board with the idea, begin development, and a few months of testing to make sure that we weren’t causing unforeseen effects.”

Have you noticed this software update? What do you think of it? Tell us in the comments!