Avoid leaving or approaching major population centers during rush hours or at the noon hour. If you can, be off the road before 5 p.m. Low or glaring light conditions, heavy traffic, fatigue of both driver and bicyclists, and the appearance of the drinking driver make this the most dangerous time of day. Night riding is not recommended. When on the highway, leave the roadway when you hear a car approaching. Always assume that the driver has not seen you.
Fog presents another danger for cyclists.
If you must ride in fog, treat it like nighttime. Tunnels are almost never designed for use by bicyclists. Use lights, flags, and safety triangles. Stand just inside the tunnel on the walkway or shoulder until your eyes can adjust to the poor light. Ride as far to the right as you can get.