Arterial Road

An arterial road, or arterial thoroughfare, is a high-capacity urban road. The primary function of an arterial road is to deliver traffic from collector roads to freeways, and between urban centres at the highest level of service possible. As such, many arteries are limited-access roads, or feature restrictions on private access. Though the design of arterial roads varies from country to country, city to city, and even within those cities, they share a number of common design characteristics. In many cities, arteries are arranged in concentric circles (commonly referred to as a ring road) or in a grid. Many jurisdictions also classify arterial roads as either principal (major) or minor.

In traffic engineering hierarchy, an arterial road delivers traffic between collector roads and freeways. For new arterial roads, intersections are often reduced to increase traffic flow. In California, arterial roads are usually spaced every half mile, and have intersecting collector(s) and streets. Some arterial roads, if having a small fraction of intersections and driveways compared to most arterial roads, are also considered to be expressways in some countries and some states of the United States.