I’ve found the worst situation is where the bike lane or path is below the grade of the road, there is no overhead lighting, and you are on the same side of the road as oncoming traffic. The light from cars in your eyes, the shadow on the ground in front of you, and oncoming bikes on the left make it nearly impossible to see. This is where really bright lights help the most. Adding rain and twists and turns to the path make it even more difficult.