The San Francisco Municipal Transportation Agency plans to upgrade its aging bus fleet with the help of more than $21 million in federal grants, city officials announced Monday.

The grants, awarded by the U.S. Department of Transportation’s Federal Transit Administration, will be distributed to 255 projects around the country, including others in the Bay Area.

About $15 million of the award will go toward new biodiesel-electric hybrid buses and more than $6 million will go toward the improvement of bus facilities.

The funding “will translate into direct rider benefits,” said Ed Reiskin, SFMTA Director of Transportation.

The new 40-foot buses will replace 18 20-year-old buses, reducing toxic emissions from the vehicles, according to agency officials. The first of the new buses is expected to arrive in early 2013.

“It’s more modern operations that are going to be more efficient and more caring for our environments,” Mayor Ed Lee said.

The federal funding is also benefiting other regional transit agencies, including BART and Alameda-Contra Costa Transit.

BART is receiving nearly $3.2 million to install more signage with real-time bus and rail arrival times at some of its intermodal stations, while AC Transit is receiving $7.5 million to purchase new fareboxes.

“We need to sustain what we have in the region, and what we have in the region is a pretty good thing,” said Tom Radulovich, member of BART’s board of directors.

Dan McMenamin, Bay City News

Want more news, sent to your inbox every day? Then how about subscribing to our email newsletter? Here’s why we think you should. Come on, give it a try.