Okla. Stat. tit. 47, § 47-12-204: Tail lamps

A. Every motor vehicle, trailer, semitrailer and pole trailer,

and any vehicle which is being drawn at the end of a combination of

vehicles, shall be equipped with at least two tail lamps mounted on

the rear, on the same level and as widely spaced laterally as

practicable which, when lighted, shall emit a red light visible from

a distance of one thousand (1,000) feet to the rear; provided that,

in the case of a combination of vehicles, only the tail lamp on the

rearmost vehicle need actually be seen from the distance specified.

B. Every tail lamp upon every vehicle shall be located at a

height of not more than seventy-two (72) inches nor less than

fifteen (15) inches.

C. Any tail lamps shall be lighted whenever the clearance lamps

and:

1. Headlamps;

2. Combination of headlamps and auxiliary driving lamps, as

defined in Section 12-217 of this title; or

3. Fog lamps, as defined in Section 12-217 of this title,

are lighted.