Okla. Stat. tit. 47, § 47-12-427

A. The triangular yellow-orange and red slow moving vehicle

emblem which meets the standards and specifications of the American

Society of Agricultural Engineers, ASAE S276.3, Slow-Moving Vehicle

Identification Emblem, shall be recognized as the official slow-

moving vehicle emblem of this state.

B. 1. All farm machinery, other machinery including all road

construction and maintenance machinery, and all other vehicles and

animal-drawn vehicles designed to operate and operating at a maximum

speed of no more than twenty-five (25) miles per hour traveling on a

highway during day or night shall display a slow-moving vehicle

emblem on the rear of the vehicle.

2. When such road construction and maintenance machinery is

engaged in actual construction or maintenance work and there is

either a flagman or clearly visible warning signs to warn of such

machinery's presence on the roadway are exempt from the requirements

of this section.

C. The emblem shall be positioned as near as practicable to the

center on the rear of the vehicle or machinery; provided however,

that in the case of a string of farm machinery or implements being

towed only one clearly visible emblem must be displayed on the

rearmost vehicle.

D. The use of such emblem shall be in addition to any lighting

devices or other equipment required by law. The failure on the part

of an owner or driver of any nonmotor vehicle to display the emblem

required in this section shall not relieve the operator of a motor

vehicle from negligence in the event of a collision. No person

shall use the slow-moving vehicle emblem except as required in this

section.

E. The evidence as to the use of such emblem or the lack of the

use of such emblem shall not be admissible in the trial of any case.