Subdivision plats are required to set forth the layout for the streets in the subdivision. The streets may be public or they may be private roads. If the streets are public, the subdivision plat must determine whether they will form a grid pattern or a hierarchical system that is dependent upon a loop road, whether there will be one or multiple connections from the subdivision to the existing streets, or whether there will be cross-connections to adjacent subdivisions.

The grid pattern of roads was formed from a national coordinate system of roads. It creates squares of land that are divided into blocks. It allows for the incremental expansion of the road system without disturbing the existing road system. It also distributes traffic and avoids concentrating traffic on a few streets.

The hierarchical road system consists of a main road upon which other roads are dependent. The hierarchical road system has streets that may end in a cul-de-sac or for which there is no through traffic. The hierarchical road system creates residential streets that conform more easily to the topography of an area.

Some developers create subdivisions with private roads, which roads are often controlled by an entrance gate. Ingress and egress to the subdivisions are often limited to one gate. A homeowners' association usually owns the roads and has responsibility for maintaining the roads. However, problems can result if the roads were not properly built or if the association does not properly budget for maintenance of the roads. When this occurs, the association often seeks to have the private roads returned to the public sector in order to avoid assessing its homeowners for the maintenance of the roads.

In recent years, more and more subdivisions are including roads that are designed for "traffic calming." "Traffic calming" is an intentional design of roads that encourages low speeds of travel. This may include the use of narrower roads, curving roads, speed bumps, or rumble strips.