Under Texas law, a vehicle is required to have a head light on each side of the front of the vehicle. Head lights are required to be used at nighttime and when light is insufficient or atmospheric conditions are unfavorable so that a person or vehicle on the highway is not clearly discernible at a distance of 1,000 feet. Texas Transportation Code Section 547.302(a) & (c). Nighttime is defined as the period beginning one-half hour after sunset and ending one-half hour before sunrise. Texas Transportation Code Section 541.401(5).
Failure to use head lights when required is a traffic offense under Texas Law.
Law enforcement officers often use the type of violation to stop vehicles on Texas highways to conduct their drug interdiction activities.