Frontage Roads: Assessment of Legal Issues, Design Decisions, Costs, Operations, and Land-Development Differences

Abstract

A policy of building frontage roads alongside freeway mainlanes avoids the purchase of access rights when upgrading existing highways to freeway standards and can supplement local street networks. It also may affect corridor operations, land values, and development patterns. The purpose of this paper is to provide a comprehensive evaluation of frontage-road design policies by (1) summarizing research results related to legal statutes affecting public access to roadways, (2) discussing access policies and practices across the states, (3) comparing land development and operations of corridors with and without frontage roads, (4) summarizing studies on access-right valuation, and (5) comparing total construction costs. In a literature review, a wide variety of options are available to agencies for limiting access to and improving flow and safety along freeway corridors. In statistical analyses of paired corridors, land near frontage roads is associated with lower household incomes, lower population densities, lower percentages of bike trips to work, lower vehicle occupancies for work trips, and higher unemployment rates than those without frontage roads. Lower employment densities along freeway corridors also emerged when frontage roads were present. Operational simulations of various freeway systems demonstrated that frontage roads may improve the operation of freeway mainlanes in heavily developed areas but not in moderately developed areas (e.g., mainly residential). Arterial systems in these simulations were supplemented by frontage roads and thus also performed better. The financial costs associated with frontage road facilities were considerably higher than those associated with non-frontage-road facilities, except in cases of extremely high access-right-of-way values. These results, in addition to efforts by other researchers, should assist in constructing a solid, formal policy for all states and regions to follow in providing access along new and existing freeways in the future.