Rules capping U.S. greenhouse gas emissions are gaining traction at the state level as federal proposals to do the same bog down in Washington.

Eight states are expected to launch their own greenhouse gas initiatives this year while 16 states have gone to court to challenge the Bush administration's refusal to allow states to regulate auto emissions.

USA Today said Monday that 17 states have some sort of cap in place on auto or power plant emissions.

Critics said companies need one set of regulations that apply to the entire nation; however USA Today said two federal court rulings in 2007 found that states do have the authority to regulate auto exhaust.

Copyright 2008 by United Press International