Back in the late-'60's I remember speed limit signs on the interstates that said "Speed Limit 65 Night 55 Trucks 55". Yes, at speeds of 70-80 mph you may be out driving the beam of the headlights. In other words if something appears in the headlight beams, you would not be able to react in time. As I have aged I have noticed my eyes are not so good at night. I really hate driving at night in the rain. Too. much. glare. I can do it if needed, but much prefer not to. The glare from some vehicle headlights is very blinding. 70 mph is about my limit at night - after 42 years of driving I know my reaction time is not what it use to be though it is still good.