Have you ever just been shy of a full-on road rage incident because some inconsiderate person was hitting you with hi-beams? Then some of this information may be for you.
We've all been on the highway and had someone "forget" and come right at us, blinding us with their hi-beams. Then there are the times when you have someone driving behind you and they put the twin spotlights right on your rearview mirror. Either instance is terrible, but have you asked yourself, "is it illegal?"
I try to always stay conscious of when I have my hi-beams/brights on. I rarely just leave them on unless on a long stretch of desolate highway. In instances like that, the better you can see critters or things in the road, the better chance you have of stopping in time.
There are very much traffic laws that deal with leaving your brights on, and yes, it can be illegal. Here's the applicable stuff from the Texas transportation code:
(1) an operator approaching an oncoming vehicle within 500 feet shall select:
(A) the lowermost distribution of light or composite beam, regardless of road contour or condition of loading; or
(B) a distribution aimed so that no part of the high-intensity portion of the lamp projects into the eyes of an approaching vehicle operator; and
(2) an operator approaching a vehicle from the rear within 300 feet may not select the uppermost distribution of light.
Putting this plainly, if there's a vehicle coming toward you, you have to shut your hi-beams off. If you are behind a car (say, close enough to see the taillights) you need to shut your hi-beams off.
I would say it's pretty doubtful you'll get a ticket for doing either of these things, except if that car in front or behind of you is a cop, but it doesn't hurt to be a good human and realize that these laws were put in place for a reason. Dim down for other drivers.