Visibility is an issue for motorcycles at all times of the day. Many accidents happen because drivers do not see motorcycles at all. They are very small, many are black or another dark color, and they tend to move quickly. Drivers just overlook them and create accidents.
On one hand, this problem gets worse at night. That small black bike can blend into a dark roadway as the sun goes down. We already know that the reduced visibility at night leads to car accidents, so it follows that it can lead to motorcycle accidents, as well.