The retrofit endeavor will cost the Commonwealth $22.5 million and will affect 8,400 buses. The work should be done by September 30, 2010 and is part of a deal to offset pollution caused by Boston's Big Dig tunnel road project. The deal will also test and attempt to clean up diesel locomotive engine emissions and off-road construction equipment. You can download a PDF of the announcement here.
Sounds like a good Christmas present to me.
[Source: Mass.gov via Green Car Congress]