San Francisco Municipal Transportation Agency plans to crack down on Muni fare evaders by bringing in more inspectors.

The transit agency plans to add 17 more employees to its team of 59 fare inspectors.

“I want to say the average is about five to seven per shift,” SFMTA fare inspector V. Lujan said of how many passengers they catch daily who have have not paid to ride Muni. “It depends on the line. It depends on the time.”

SFMTA figures show an increase of about $14 million in rider revenue compared to last year. But the agency knows there are still fare cheats taking advantage of the system.

Muni estimates that about one in every four of its riders are not paying their fare share.

One of the problems SFMTA currently has is tracking how many people are legally riding for free.

During a news event at the Castro neighborhood Muni station, which included Mayor Daniel Lurie, Muni leaders announced a new effort to sort out riders from cheats. The plan includes asking those who are legally riding for free to start tapping a smart phone or pass so the agency can get better tracking info.

“One of the benefits of this initiative is getting more people tapping, which will give us better data,” said Julie Kirshbaum, SFMTA director of transportation. “We estimate about half of our customers pay in an invisible way like through an app or are free like our youth.”

Anyone 18 or younger can currently ride Muni free of charge.

Board of Supervisors President Rafael Mandelman is cheering the new effort to crackdown on fare evaders.

“Because of our great fare inspectors, when you get on that train or bus, you are going to know that those people are paying,” Mandelman said.

Riders who spoke to NBC Bay Area on Tuesday said uniformed fare inspectors on buses and trains also make them feel a little safer on their commutes.