Feds move forward on asking states to track car emissions

Federal officials moved forward with requirements that states track vehicle emissions on federal highways after months of delays that prompted California and seven other states to sue. But they might repeal the new rules next year anyway, rendering this week's decision moot. The rules require state transportation departments to track on-road emissions of greenhouse gas emissions by looking at gas purchased and miles traveled on federal highways. States must then set emissions targets, with the goal of reducing them over time. Emissions from cars, trucks and other vehicles make up roughly 27 percent of the nation's total greenhouse emissions.In the short term, the rules will move forward. But federal officials will also undertake a fresh review of whether they're necessary or could be made better.