The city of Ann Arbor, MI is replacing its entire municipal bus fleet over the next two years and all the new buses will be hybrids. The Ann Arbor Transportation Authority will be getting the first fifteen units this fall with the rest of the 69 vehicle fleet being supplanted during 2008 and early 2009. AATA provides transit bus services to the city and surrounding communities.

The extra cost of the first twenty buses is being covered by a federal grant, although it's not clear at this point how the other forty-nine buses will be paid for. The buses are being built by California-based Gillig and they use the GM Two-Mode hybrid system with a nickel metal hydride battery. The early experience of hybrid buses in Seattle proved to be disappointing with hybrid buses getting lower mileage than conventional buses. A later study conducted by the National Renewable Energy Laboratory compared the hybrid and conventional buses over the same routes and duty cycles for a six-month period and found the hybrids to have a 27 percentage advantage.

[Source: MetroMode via YpsiDixit]