Wyo. Stat. § 31-5-910 (2026)

Every vehicle including those listed in W.S. 31-5-901(c), except
as otherwise provided in this act, upon a highway within this
state at any time from one-half (1/2) hour after sunset to
one-half (1/2) hour before sunrise and at any other time when,
due to insufficient light or unfavorable atmospheric conditions,
persons and vehicles on the highway are not clearly discernible
at a distance of one thousand (1,000) feet ahead shall display
lighted head and other lamps and illuminating devices as
respectively required for different classes of vehicles, subject
to exceptions with respect to parked vehicles. Stop lights, turn
signals and other signaling devices shall be lighted as
prescribed for those devices.