The San Diego Metropolitan Transit System (MTS) says it is purchasing 53 compressed natural gas (CNG) buses to replace diesel units that are being retired from service.

These 40-foot, low-floor buses from New Flyer are scheduled to come online starting next month, and deliveries will continue through August, MTS says. The price tag for the new CNG fleet is $22.3 million.

"These are significant purchases for our agency," says Paul Jablonski, CEO of MTS. "Our continuing replacement of buses ensures that our passengers will enjoy reliable and comfortable service. We will soon have one of the nation's most modern fleets."

Thirty-one of the CNG buses will operate out of the MTS bus yard on Imperial Ave. in San Diego, and 22 will originate from a maintenance facility in Chula Vista.