Texas doesn't need to be a CARB state, Texas will however pay $2,500 to assist in the purchasing of an Electric, LPG or CNG vehicle. http://legiscan.com/TX/text/SB1727/id/857706
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There is even this old statute http://www.statutes.legis.state.tx.us/D ... V.2158.htm
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Sec. 2158.005. PERCENTAGE REQUIREMENTS FOR VEHICLES USING ALTERNATIVE FUELS. (a) Not later than September 30, 2010, a state agency that operates a fleet of more than 15 motor vehicles, excluding law enforcement and emergency vehicles, shall have a fleet consisting of vehicles of which at least 50 percent
use compressed natural gas, liquefied natural gas, liquefied petroleum gas, methanol or methanol/gasoline blends of 85 percent or greater, ethanol or ethanol/gasoline blends of 85 percent or greater, biodiesel or biodiesel/diesel blends of 20 percent or greater, or electricity, including electricity to power a plug-in hybrid motor vehicle.
It might be enlightening to count Texas government purchases of say GM Volts or Tennessee LEAFs compared to their peers in the rest of USA.