Long ago, running as twilight came on, I noticed something odd. Those driving east had the sun behind them, and were more visible, yet they had their lights on because they were facing a darker sky. Those driving west were less visible against the darkening background, yet they faced a lighter sky and did not turn on their lights.
Turns out I always turn lights on in such HDR situations producing low-contrast areas: if you have a hard time seeing those in front of you, those behind you have a hard time seeing you. Same goes for haphazard tree shades, even though it looks like it's bright enough, the alternating areas of bright and dark makes you difficult to see. Also, I have excellent eyesight which biases me into what is seeable and what is not, but I try to take into account those who don't, and act accordingly.
