UT: In May 2007, Utah joined the Western Climate Initiative, a joint effort to reduce regional greenhouse gas emissions and address climate change. Other members include Arizona, California, Montana, New Mexico, Oregon, Washington, and the Canadian provinces of British Columbia and Manitoba. By agreeing to the Initiative's regional goal, members commit to adopt California's GHG standards for vehicles.
Links:
[1] http://www.westernclimateinitiative.org/ewebeditpro/items/O104F13006.pdf