The agency’s Office of Inspector General previously flagged concerns about its management of the $5 billion program.

As the U.S. undergoes a transition to clean energy, yellow school buses are coming along for the ride. The problem is that there's half a million of them on the roads, and they pollute the air our ...

Add Yahoo as a preferred source to see more of our stories on Google. More diesel buses are on the way out as Michigan invests $44 million in cleaner school transportation. The number of clean-powered ...

Officials say the measures, allowing the state to purchase diesel buses, come in response to changing environmental policy ...