BART’s new police chief is a 22-year veteran of the department who has been doing the job on an interim basis for the past nine months, agency leaders announced Friday morning.

As he gets started in the permanent role, Chief Ed Alvarez will oversee a substantial increase in the number of his officers who patrol trains and stations on nights and weekends, as BART grapples with rising crime and declining ridership.

Alvarez, who was previously a deputy chief in charge of the BART Police Department’s Support Services Bureau, has been in the interim job since Chief Carlos Rojas retired last April.

“I am excited for the opportunity to move the department forward and improve the relationship with our riders and our employees as we work together to make BART the safest transit system in the country,” Alvarez said in a statement.

He will be tasked with leading a department that is in the midst of a hiring spree, grappling with the challenge of keeping the peace in a system where the Bay Area’s social problems often play out, and being closely scrutinized for racial disparities in how often police use force or ticket riders for violations.

BART officials have plans for riders to see a lot more of the police department in the near future.

On Thursday, BART’s board approved a pilot program in which unarmed “ambassadors” from the police department’s community service officers unit will ride trains during the evening commute and late-night hours. That six-month program will start in February.

And in announcing Alvarez’s hiring Friday, BART leadership also unveiled a separate plan to have a dozen standard, armed police officers ride trains and patrol platforms on nights and weekends, as part of a new “train team” that starts its work next week.

Put together, BART official say, that amounts to a total of 22 new BART police employees aboard trains at a time when many riders say they feel uneasy in the system.

“We must do more to ensure all riders feel safe and to prevent crime on BART,” said BART General Manager Bob Powers, the agency leader who himself is just a few months into his job. “Ed Alvarez brings the internal knowledge coupled with the creative thinking to better serve our riders, support our officers, and increase accountability without delay.”