There are different rules for night driving.
If you’re an experienced night driver, especially an experienced long-distance night driver, you can probably skip this step. This is for ordinary drivers who go on holidays perhaps once or twice a year, maybe slightly more often, but don’t really drive a long way at night very much.
Fatigue is a major problem. It’s very hard to diagnose, because by the time you’re tired enough to be a danger on the road, your mental state is usually too diminished to be an effective judge of itself.
It really is best not to drive during times of the day (night) at which you would normally be asleep. It is especially ridiculous to put in a big week at work and then drive overnight, interstate or for several hundred kilometres. Likewise, a big week away on holidays, followed by an overnight drive home is inviting disaster.
Fatigue is not the only risk. Animals are more active at night, and the risk of hitting an animal is much higher in low light conditions. It’s actually insanely high at dawn and dusk in the country, because animal activity is high, and the low light levels compromise your visual acquity.
It’s false economy to drive when your body is yelling at you to sleep. Dawn and dusk are bad times to be on country roads, and excellent times to be stopped having breakfast and dinner, respectively.