U.S. transit systems testing the technology see economical as well as environmental benefits. Conversion to other alternative fuels — biodiesel, natural gas and propane autogas — continues growth.

Second annual Bus Maintenance Survey finds that many agencies around the nation are experiencing difficulties with alternative propulsion, as they continue to add new equipment in the shop to service as well as learn new ways to make repairs to the vehicles. Meanwhile parts issues, including concerns about availability, lead times and frequent failures, remains the biggest issue.

Today, the maturation of alternative fuels has made it easier for transit agencies to implement programs than it was for early adopters in the 1990s. Even still, there are many lessons to learn from the early pioneers, including being aware of possible infrastructure and training investments.