High gas prices may soften the opposition of some states to offshore drilling.
According to federal officials, districts like Oakland, Calif., harm private bus firms by using city transit buses.
A report by the Brookings Institution looks at the 100 largest metro areas in the US, using data on residential energy consumption and highway transportation.
Thursday's ruling makes it the second state to legalize same-sex marriage.
It's a 50 percent possibility, a new Scripps study finds, which would squeeze water supplies in Arizona, California, Nevada, and New Mexico.
With stepped up campaigning, Obama seeks to make inroads into Clinton's Hispanic support.
Clean energy work is a rapidly growing industry, but critics say it's no panacea for unemployment.