Note that every car, except the SUV can only drive up half a block. So make sure to place asphalt slopes, slabs or normal slabs on your road.
Asphalt is used to construct roads. For height variation of your road you can use asphalt slopes, flat asphalt slopes and asphalt slabs.
You can add street markings to your road with painters. Select the type of marking you want by sneak + right-clicking the painter or the yellow painter and clicking on the type you want. Place markings on the ground by right-clicking.
The street safety can be increased by adding guardrails to the side of roads, so that you wont get stuck off the road.
Signs can be edited by right-clicking them. You can put text on both sides of the sign. Each side of the sign can have 4 lines of text.