BART directors voted unanimously this month to approve a plan to improve cellphone connectivity and provide seamless Wi-Fi coverage in a gradual process over five years.

BART officials said the project will involve constructing new Wi-Fi and Bluetooth infrastructure, which will enhance cellular coverage to drastically reduce dropped calls, provide reliable connectivity for video and audio streaming while riding and waiting, and allow for improved app functionality, even in underground stations.

They said the project also lays the groundwork necessary for potential future mobile ticketing and on-demand personalized service information on a riders’ device of choice.

New BART General Manager Bob Powers said the advances are part of his emphasis on improving customers’ experience while generating revenue for the transit system by expanding underground cellular and fiber optic infrastructure.

“We must bring our technology up-to-date and expand broadband coverage to better compete in the transportation market and provide convenient, easy to use transit,” Powers said in a statement.

The plan calls for BART and the San Francisco Municipal Railway to partner with Mobilitie, the country’s largest private wireless infrastructure company, to add underground cell coverage to three Muni tunnels — Sunset, Twin Peaks and the Central Subway — within three years.

The next phase will require Mobilitie, which is based in Newport Beach, to build new wireless systems in all BART stations within four years.

The third phase of the proposal will extend wireless services from the stations to BART’s new “Fleet of the Future” train cars.

The final phase involves installing new commercial fiber optic cables along some BART and Muni rights of way.

The four projects are expected to bring in more than $243 million over 20 years, with all capital and operating expenses borne by Mobilitie, according to BART officials.

“This digital railway project opens up the potential for BART to offer world class digital communication to our riders and to modernize our business practices in the field,” said BART Chief Information Officer Ravi Misra, who led the planning and negotiations for the project.