Road hierarchy

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To reduce costs, a road hierarchy (bottom) channels travel demand (desire line thickness between settlements, top). Higher-class direct roads serve high-demand trips; lower-demand trips follow less direct routes on lower-class roads.

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Basic functional road classes (arterial, collector and local) along the mobility-access continuum. Naming, range and subdivisions of each class vary by administrative division.

A road hierarchy is a system for categorizing roads. Road networks worldwide are typically organized according to one or more schemes:

Functional classification reflects a road’s intended role, balancing mobility (efficient through movement) and access (reaching properties) by defining a clear hierarchy from arterials (including limited-access roads and controlled-access highways) to collectors and local roads.
Administrative classification mirrors government tiers responsible for funding and maintenance, creating a hierarchy from national to local roads.
Design type classification groups roads by geometric and operational characteristics, such as lane configuration and access control, and does not always form a strict hierarchy.

While conceptually distinct, these classification systems often overlap in practice. Roads of higher administrative status typically serve higher functional roles and follow higher design standards, though exceptions are common. Most countries emphasize either functional or administrative classification for legal and planning purposes, while design standards are applied during implementation.

The related concept of access management aims to provide access to land development while ensuring traffic flows freely and safely on surrounding roads.