In Virginia, there are several types of turns that could be classified as illegal. Many drivers consider illegal turns to be a relatively small matter. However, the dangers they actually pose can be more severe than you may expect.
FindLaw notes that people often think of illegal U-turns when discussing the topic of illegal turns in general. This is an act in which a driver will take a "U-shaped" turn in order to go back the way they were coming from on an adjacent lane. In some areas, these turns are perfectly legal. In other areas, there are signs posted telling drivers they aren't allowed to make a U-turn. This is because the area in question is too dangerous. Perhaps the concentration of cars is too high, the speed limit is too fast, or the intersection is too complex.
U-turns aren't the only illegal turns. Other examples include taking right-handed turns on red lights at intersections where it's disallowed, taking left-handed turns at most red lights, or disregarding traffic signs that disallow you from turning down roads at certain hours of the day.
All of these turns are illegal because you could end up seriously hurting yourself or others if you take them. You could be going against oncoming traffic, turning into a road where you don't have clear vision, or turning down a road that may suddenly become restricted to buses or one-way travel in the opposite direction.
In order to avoid these dangers, it is important to heed traffic signs and take illegal turns as the serious matter they are. If you have been involved in a crash because of a wrong-way turn, you may wish to seek legal representation.