Okla. Stat. tit. 69 § 636.2
The Department of Transportation is hereby authorized to use the County Road Machinery and Equipment Revolving Fund to purchase new or used road and bridge construction and maintenance machinery and equipment for lease or lease-purchase to counties. Such machinery and equipment shall include, but not be limited to, the following: asphalt pavers, automobiles, backhoes, bridge painting machines, cranes, elevating graders, fork lifts, front-end loaders, motorized weed sprayers, mowers, paving breaker tampers, pickups, power shovels, snow plows, street sweepers, trucks and wheel and crawler tractors. The Department of Transportation may make such purchases only if requested to do so by a board of county commissioners or circuit engineering districts pursuant to the provisions of Section 302.1 of this title, and may not act in behalf of any county in the purchase of any road machinery or equipment except as provided for in this act.
Okla. Stat. tit. 69, § 636.2