There is a lot that you can do with component roads. Basically, they give you edit access to all of the parts of the road assembly: lanes, shoulder, median, etc. For example, you can add a lane to a section of road, change its width, assign a new material, and customize it as you need to. This tutorial covers the essentials to get you started drawing and editing component roads. Exercise 3 shows you another benefit of component roads, which is the ability to add road decorations such as street lighting.