An infographic by Adam Nagourney and Jennifer Haberkorn

On the surface, the challenge has as much to do with algorithms as people: the sheer volume of data, data so vast that researchers can’t easily manage it all.

“It’s daunting,” said William Ross, director of mobility for Transparent Transport, a nonprofit group that advocates for smart transport in California.

The same is true for California, where Mr. Ross says data produced by public transit has been muddled by federal regulators.

A 2018 estimate by the California Public Utilities Commission found that about 13 percent of the state’s transit systems had been closed for months, with uncertain futures.

In other cases, trains or buses are on the track, but operating outside their normal routes. In one case last year, a commuter train derailed and crashed in the San Francisco Bay Area. Investigators think they were traveling in an area that wasn’t on the route; that was recorded.

California’s Deputy Secretary for Transportation, Mark Grossi, told a conference of transit officials last year that the transportation system has not kept up with the data requests that agencies have made of the state Transportation Agency.

In some cases, Mr. Grossi said, departments aren’t always getting the records they need. In others, he said, they are “overwhelmed by federal requirements.”

Transparency advocates say they worry that government agencies are unable to gather as much data as is needed to address the challenges they face.

The California Public Utilities Commission has issued a second call for transit providers to provide more data on their systems, saying that the state “needs more and better data, and that the long-term sustainability of public transportation systems depends upon it.”

In 2017, the commission received more than 6,800 applications for data on transit systems in the state.

“It’s too hard for us to do things anymore,” said Mr. Ross, who said it was actually the system’s willingness to collect that many data that was so puzzling.

Transparency advocates in Massachusetts and elsewhere say these confrontations reflect continuing financial and organizational problems that hinder the ability of local officials to communicate and collaborate with people who design, build and maintain buses, trains and other transit systems.

“The kind of leadership that exists in these transportation cities is necessary,” said Anabel Rosenós, director of planning and management for the Coalition for a Sustainable Boston Region, a nonprofit group. “But there’s a mismatch between our desire to govern and the reality.”

The Massachusetts Bay Transportation Authority, known as the MBTA, has instituted initiatives to share data.

The agency is not always successful, however. Since 2017, several large contracts have involved shared data. Another initiative was canceled, and other plans have stalled.

“There’s a message to the public that it’s too expensive to help collaborate with the public,” said Mr. Ross.