SunLine Transit Agency is a transit operator in Riverside County, California, United States, providing bus service to more than 3.5 million passengers per year in the Palm Springs Area. Service extends into San Bernardino Transit Center during peak hours.[1][5] In 2024, the system had a ridership of 2,840,200, or about 8,400 per weekday as of the second quarter of 2025.
The service area covers 1,120 sq mi (2,900 km2), bounded approximately by the San Gorgonio Pass on the west and the Salton Sea on the southeast.[6]: 13 In addition to its transit operations, SunLine regulates local taxi services (as the SunLine Regulatory Administration, a division of the SunLine Services Group)[7]: 25 and sells CNG and hydrogen to the public from dispensers at its Thousand Palms and Indio operations facilities, under the brand SunFuels.[8][9]: 3
SunLine is governed by a board of directors with 10 members[11]
1 City Council member From Palm Springs
1 City Council member from the 9 cities in the Palm Springs Area that are not Palm Springs City.
1 from the Riverside County Board of Supervisors, that represents the Palm Springs Area (District 4)
Chair
Nancy Ross
Vice Chair
Lynn Mallotto
Chief Executive Officer
Mona Babauta
Facilities and bus fleet
Early fuel cell buses
XCELLSiS ZEbus refueling at Thousand Palms facility
Thor/ISE ThunderPower in service with AC Transit after initial operations with SunLine
The initial fleet included 22 buses in 1977. SunDial paratransit operations started in 1991.[12]: 11
The SunLine Board of Directors adopted a resolution in 1992 to convert their fleet to alternative fuel, and became the first transit agency in the United States to do so in 1994, using compressed natural gas (CNG) buses.[12]: 11
Starting in 2000, SunLine began limited operations with hydrogen fuel cell buses, installing a hydrogen fuel station using a Stuart Energy electrolyzer to supply the XCELLSiS ZEbus for a 13-month trial.[13] The first revenue operations were conducted with the Thor/ISE ThunderPower fuel cell bus, using an ElDorado National EZ-Rider II chassis, between November 2002 to February 2003.[14] By that time, SunLine also had installed a HyRadix methane reformer to generate hydrogen.[15]: 6 SunLine tested a hydrogen hybrid internal combustion engine (HHICE) bus in early 2005; the bus was subsequently sent to Winnipeg Transit for cold weather testing.[16]
STA plans to convert their fleet to zero-emission buses (ZEB) by 2035, with only ZEBs purchased starting in 2021.[17]: 1, 3 Due to the relatively long fixed routes, the final mix of ZEBs is expected to be mostly hydrogen fuel-cell buses.[17]: 9
SunLine has two operations and maintenance facilities: one (including the administrative offices) in Thousand Palms, and another in Indio. As of 2021[update], on-site refueling and charging capabilities include an electrolyzer that can produce 900 kg/d (2,000 lb/d) of hydrogen at Thousand Palms, which came online in 2019, and six 80 kW AC/DC battery-electric bus chargers, three each at both Thousand Palms and Indio.[17]: 1, 3, 17 Hydrogen dispensers (using delivered liquid H 2) and additional chargers are planned for both facilities.[17]: 7–8
Hydrogen production started in November 2000. Two electrolyzers and a natural gas reformer were part of the initial installation. One electrolyzer, supplied by Teledyne Brown, generated 40 cu ft (1.1 m3) per hour using 7.5 kW of electricity, supplied by solar panels; the other electrolyzer, supplied by Stuart Energy, produced 1,400 cu ft (40 m3) per hour. The reformer produced 4,200 cu ft (120 m3) per hour.[18] The HyRadix Adéo reformer was installed at the end of 2003.[19]
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