DENVER—The governors of two natural gas producing states are in Detroit as part of an effort to push the use of vehicles powered by natural gas.

Colorado Gov. John Hickenlooper and Oklahoma Gov. Mary Fallin were meeting Monday with executives at Chrysler, General Motors and Ford. They also planned to tour auto manufacturing plants and drive some natural gas vehicles.

Colorado and Oklahoma are among 13 states that have signed a memorandum promising to invest in natural gas vehicles when they replace older cars and trucks. The aim is to create new demand for domestically-produced natural gas as well as help make such vehicles more affordable for average buyers.

The other states that have signed on are Kentucky, Louisiana, Maine, Mississippi, New Mexico, Ohio, Pennsylvania, Texas, Utah, West Virginia and Wyoming.