Planning's Role in Standards for Future Highways

Many states have prepared functional classification studies. These studies involve the determination of the level of service that a road is expected to provide and evaluation of such factors as length of trips, speed of operation, directness of routing, degree of access control, degree of land service, and freedom of movement. Highway planning engineers should define the functional classes listing the objectives and descriptions of each classification and gather the data used determine the classification of each highway. Designers and planning engineers should cooperatively develop design standards which reflect the desired service to be provided by each functional class. Highways can be classified into three broad groups: arterial, collectors, and locals. Illinois has chosen high design speeds and levels of service for the arterial system. The highest class of arterial has full control of access. The design speeds and level of service for collector highways are lower than for arterials, and the local system would have no access control with no requirements for level of service.