The governors of Colorado, Oklahoma, Pennsylvania and Wyoming have agreed to work together to encourage U.S. automakers to develop affordable natural-gas vehicles.
The governors signed a memorandum of understanding Wednesday saying they would they would seek a joint request for proposals.
The states would work to determined how many natural gas vehicles each could commit to buy. The request would specify that the ultimate cost of the vehicles should be comparable to gasoline-powered vehicles.
The agreement was announced at the Colorado Natural Gas Vehicles Coalition Workshop in the Denver suburb of Englewood.