NextBus DC, a popular smartphone app that tracks Metrobus arrivals, has stopped working. (Sarah L. Voisin/The Washington Post)

A popular smartphone app that tracks Metrobus arrivals has stopped working.

NextBus DC, which uses Global Positioning System tracking and other data to determine when the next bus will arrive at a stop, quit working a few weeks ago after a contract ended between companies that provide the data to riders.

The data for NextBus DC was provided by a company called NextBus in Emeryville, Calif. But a contract between the company and Ken Schmier — who invented the bus-tracking technology — ended in mid-December.

The Emeryville firm said it would no longer provide the “customized data feed,” according to Larry Rosenshein, vice president of sales, marketing and business development of NextBus.

“The time, effort and energy it takes to supply the customized feed doesn’t make sense when the same data is available through [Metro’s] Web site for any third-party developer,” he said.

Schmier said he is working with a developer to change the app’s software so that it becomes functional again. He said he has received 7,000 complaints about the service ending. He said he expects that it will take about a week for the app to be back online.

Metro said it was “not involved in the contract dispute” between the companies and said NextBus DC is “not officially supported” by Metro, according to Metro chief spokesman Dan Stessel.

He said riders can access information on when the next bus arrives by going to Metro’s Web site on a desktop or mobile device or by telephone.

Metro has had a contract with NextBus to track bus arrivals for several years using a Web-based system, according to Rosenshein.

The NextBus DC service interruption was first reported by the Washington Examiner.