Sun Tran Upgrades CNG Fleet with Five New Buses


Sun Tran, the public transportation operator serving Tucson, Ariz., will introduce five new – and smaller – compressed natural gas (CNG) buses into its fleet this week.

According to its website, Sun Tran has over 250 buses in its fleet, and 45 of them run on CNG. The five new vehicles will replace 14-year-old CNG buses, decreasing the average age of Sun Tran's fleet from 5.97 years to 5.51 years.

The standard length of a Sun Tran bus is 40 feet, but the new vehicles are 35 feet long. Sun Tran says it purchased smaller CNG buses after evaluating outside agency studies and reports to determine the standard industry approach to balancing fleet vehicle types to maximize service efficiencies.

According to Sun Tran, research showed smaller buses have lower operating/maintenance costs and better fuel economy; better maneuverability in neighborhoods and through roundabouts; and some flexibility for specialized service.

Sun Tran says the replacement buses also utilize a newer CNG engine, which produces lower emissions than standard fueled vehicles and older CNG vehicles. The newer technology of the EMP cooling system utilizes eight electric fans in place of an engine-driven fan, which allows for better fuel economy and runs the system at optimal temperatures to ensure more efficient cooling of the engine, Sun Tran adds.

“The purchase of these new buses was in response to the needs of the community and demonstrates the city's and Sun Tran's commitment to providing a healthy environment,” says Kate Riley, general manager of Sun Tran. “Sun Tran understands the importance of this investment, as it contributes to a sustainable community.”

Purchased with funding from the Federal Transportation Administration, City of Tucson and Regional Transportation Authority, the CNG buses cost just over $508,000 each.

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