The three main classifications of road intersections include the T intersection, the four-leg intersection and the multi-leg intersection, which has five or more legs. Roundabouts are another option, but are not as common. A T intersection is one where one roadway ends at another instead of continuing on beyond that street. It may be regulated by a stop sign or stop lights, and have one or more lanes. Larger T intersections usually have left and right turn lanes.
Four-leg intersections are the most common, formed when two streets cross each other, usually at between a 75 to 90 degree angle. On quiet four-legs, such as in residential areas, stop signs are generally sufficient for traffic control. Busy four-leg intersections usually have multiple through lanes and left turn lanes, all controlled by stop lights. They may also have medians to divide two-way traffic and to make crossing the intersections easier.
Multi-leg intersections are usually necessary in large cities and can be the most difficult to navigate. Plenty of signage is needed to guide drivers to and from the correct lanes, along with stop lights and left turn lanes. Since these intersections have five or more legs, those legs may intersect at tighter angles than the norm.
Roundabouts are more common in Europe than North America. Instead of all streets meeting at an intersection, they all meet at a circle. Drivers merge into the traffic circle and follow it around until they get to their desired exit. If a mistake is made, a driver just goes around the circle again. Directional signage and sometimes warning lights are used to guide drivers.