Climate groups say the transportation bill contains steps in the right direction but falls short of transformational.
A coalition of Northeastern states is looking to craft a regional cap-and-trade system for cars.
Financial incentives helped push electric vehicle sales to top gas and diesel options in the oil-exporting country.
Stakeholders said cutting greenhouse gases from transportation will be more complex than power plants.
More transit and less road widening could set the bar for regional climate change coalition, advocates say.