March 1, 2021. The San Diego Metropolitan Transit System (MTS) hit a major clean-air milestone today by officially retiring the last of its diesel buses and adding two more electric buses to its fleet.  The agency has a long history of adopting clean fuel technology and is on a path to convert its entire bus fleet to zero emissions by 2040.

“MTS retiring the last of its diesel buses from its fixed-route fleet is a monumental leap forward in air quality,” said Nathan Fletcher, MTS Board Chair and Chair, San Diego County Board of Supervisors. “It represents our commitment to environmental justice, sustainability, air quality and to being one of the leaders nationally in achieving these ambitious environmental standards.” 

Replacing the last diesel buses will be 24 compressed natural gas (CNG) express commuter buses built by Motor Coach Industries (MCI) – one of the world’s largest independent global bus manufacturers.  “Not only do the new MCI CNG buses offer an improved riding experience for our customers, we get substantially better air quality results from them as well,” said Sharon Cooney, MTS Chief Executive Officer. “There will be a 100% reduction in particulate matter, and a 98% reduction in NOx emissions over the diesel counterparts.”

The new express commuter buses will offer 57 comfortable forward facing seats, are designed for highway speeds, and offer touring class comfort and safety. The vehicles will operate out of MTS’ East County Division in El Cajon, serving passengers on the Rapid Express 280 (Escondido-Downtown San Diego) and Rapid Express 290 (Rancho Bernardo-Downtown San Diego.

“For nearly three decades we’ve led the transition to CNG propulsion, having delivered nearly 14,000 CNG buses and coaches across North America. Today, we’re proud to support the San Diego MTS in achieving this low-emission milestone. With clean, safe, and readily scalable technology, CNG emits significantly less nitrogen oxide than diesel engines – lending immediate impact on improving air quality,” said Chris Stoddart, President, New Flyer and MCI. “MTS has long pioneered sustainable mobility, having been the first agency in America to adopt CNG into its fleet nearly 20 years ago. Congratulations on yet another leap forward to cleaner air, sustainable transit, and more livable communities.”

At the same time as retiring the diesel fleet, MTS also added two GILLIG zero-emission battery electric buses, upping the agency’s total to eight. MTS began its zero-emission bus pilot program in 2017, and intends to complete a full transition to 100% zero emissions fixed-route vehicles by 2040.