When driving at night, what should you do?

At night, your headlights will usually be the main source of light for you to see by and for others to see you. You cannot see nearly as much with your headlights as you see in the daytime. With low beams you can see ahead about 250 feet and with high beams about 350-500 feet. You must adjust your speed to keep your stopping distance within your sight distance. This means going slowly enough to be able to stop within the range of your headlights. Otherwise, by the time you see a hazard, you will not have time to stop. [California Commercial Driver Handbook]