Darkness

We are not night animals, so our night vision is not great

When the sun sets, our visual system changes entirely. It goes from color to black and white. It is like changing the film in a camera, from color to black and white. Night vision works quite different ly from day vision. One difference is that night vision is more peripheral. This is not a problem, as riding mainly uses peripheral vision anyway. We are not night animals, so our night vision is not great.

Night riding

At night your depth and speed perception is less than in daylight

A bigger problem is that our depth vision gets much worse. At night, you cant judge the distance of oncoming headlights very well. Likewise your estimates of how fast cars are travelling towards you is much worse. Riding at night is different from riding during the day. At night your depth and speed perception is less than in daylight. How far away is that car, and how fast is it traveling towards you? You know less than you think. You see the oncoming headlights, but judge their distance and speed poorly. So be more careful when pulling into a traffic flow, or changing lanes at night. Those lights may be closer than you think!

Blinding headlights

Sooner or later, you will encounter blinding oncoming headlights. Dont look at them!

Drivers are supposed to adjust their headlights so they dont shine into the eyes of oncoming traffic. However some dont, and even if they do, they could be coming up a rise which shines their lights into your eyes. Sometimes the lights of big trucks are so bright, it doesnt matter how they adjust them. One way or another, sooner or later, you will encounter blinding oncoming headlights. Dont look at them! Look to the side of the road, to see the line of the road markers, or look to the line of traffic ahead. As one tends to go where one looks, if you look at the oncoming headlights you may go that way. Fix your vision on a point of the road that you can see, and focus on that.

Sunrise, sunset

If the setting sun is behind you, other drivers cant see you as well

Sunrise and sunset are particularly dangerous, as the sun shines in your eyes, so you cant see. On a bike you can raise your left hand to shade your eyes, but this reduces your control, and is dangerous. Another option is to drop your head, so the top of the helmet acts as a sunshade. Or just squint. The flip side of this problem is if the sun is setting behind you, the other traffic cant see you. Be aware, if the setting sun is behind you, other drivers cant see you as well. Give them especial latitude.