In the USA, a frontage road (also access road, service road or feeder) is a non-limited access road running parallel to a higher-speed road, usually a freeway, and feeding it at appropriate points of access (slip ramps). They are ubiquitous in Texas and are also found in Missouri (along Interstate 44 between St. Louis, Missouri and Springfield, Missouri, and U.S. Highway 67 between Festus, Missouri and Fredericktown, Missouri) and numerous urban areas. In Canada, the term service road is more commonly used to describe a frontage road.

Frontage roads give indirect access to abutting property along an expressway, either preventing the commercial disruption of an urban area that the expressway traverses or allowing commercial development of abutting property. They add to the cost of building an expressway due to costs of land acquisition (but that might be offset on occasion, see below) and the costs of paving and maintenance; however, the benefits of nearby real estate can more than offset the cost of building the frontage roads. Furthermore, a frontage road may be a part of an older highway, so the expense of building a frontage road may be slight. Conversely, the existence of a frontage road can increase traffic on the main road and be a catalyst for development, hence there is sometimes a explicit decision made not to build a frontage road.

The Stemmons Freeway in Dallas, Texas illustrates the occasional practicability of the frontage road: the real estate developer John Stemmons offered free land to the Texas Highway commission in which to build a freeway (Interstate 35E) on terms that the state build the freeway with frontage roads that would give access to property formerly of slight value that he owned along the route. The state was able to reduce its costs (much of it the cost of land acquisition) of building the freeway, and the developer profited handsomely from lucrative development along the freeway.

In China, roads running next to expressways, taking outgoing traffic and feeding incoming traffic, are called either service roads or auxiliary roads (fudao locally). Where expressways cross larger urban areas, such frontage roads may run next to the expressway itself. Much of the Beijing portion of the Jingkai Expressway, for example, has, in fact, China National Highway 106 acting as a split-direction frontage road.

See also

• Collector/distributor road