The San Diego Metropolitan Transit System (MTS) hit a major clean-air milestone: retiring the last of its diesel buses and adding two more electric buses to its fleet.

“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).

“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 CEO. “There will be a 100-percent reduction in particulate matter, and a 98-percent reduction in NOx emissions over the diesel counterparts.”

The new express commuter buses will offer 57 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).

“Today, we’re proud to support the San Diego MTS in achieving this low-emission milestone,” 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.”

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. The two California-made GILLIG buses are the first of seven to be delivered to MTS. GILLIG’s zero-emission battery-electric buses are equipped with the Cummins electrified powertrain and are supported by a nationwide service network. Built on GILLIG’s low floor platform, the buses ensure parts and training commonality with MTS’s existing GILLIG fleet. Equipped with six onboard batteries, each bus has a battery capacity of 444 kWh, providing an estimated range of 140 miles. The buses utilize energy recovered from a regenerative braking system and feature a direct-drive traction motor with peak torque of 3500 Nm (2,582 lbs.-ft.).

“We are excited to partner with the San Diego Metropolitan Transit System as they work towards their Innovative Clean Transit goal of a 100-percent zero-emission fleet by 2040,” said Bill Fay, GILLIG VP of sales. “The new battery-electric buses support MTS’s commitment to excellent service and cleaner air for the communities they serve, and GILLIG is proud to be a part of this step forward.”