Functional classification defines the nature of the traffic channelization process by defining the part that any particular road should play in serving the flow of trips through a highway network. Essentially, functional classification channelizes traffic flow by travel demand which the highway services. 公路功能分类是通过研究公路的服务功能,确定特定公路在公路网中扮演的角色,并为相应的交通出行提供服务,功能分类实质是按服务需求疏导交通。