Okla. Stat. tit. 47, § 47-15-104: State highway commission to adopt sign manual

The State Highway Commission shall adopt a manual and

specifications for a uniform system of traffic-control devices for

use upon streets and highways within this state. Such uniform

system shall correlate with and, so far as possible, conform to the

system then current as approved by the American Association of State

Highway Officials, and the manual so adopted may be amended or

revised from time to time as the Commission may deem necessary. The

manual so adopted and any amendments or revisions thereof shall be

published by the State Highway Commission and one copy thereof shall

be distributed free of charge to the local governing bodies of

counties and incorporated cities and towns.