Red and white regulatory signs tell you about regulations you must follow. For example, the DO NOT ENTER sign tells you there is danger ahead because vehicles will be coming toward you, usually on a freeway off-ramp or one-way street.
The WRONG WAY sign may accompany the DO NOT ENTER sign. This rectangular red and white sign is a traffic regulatory sign. If you see one or both of these signs, drive to the side and stop; you are going against traffic. When safe, back out or turn around and go back to the road you were on. (At night, road reflectors will shine red in your headlights when you are going the wrong way.)
A red circle with a red line through it always means NO. The picture inside the circle shows what you cannot do. The sign may be shown with or without words under it.