Frontage Roads Research Articles

Dynamic control and traffic performance in a freeway corridor: a simulation study

This paper describes simulation studies that were conducted to assess the performance of a freeway corridor control system. The system combines an advanced traffic management system with a motorist information system that provides route guidance to individual drivers. It has a hierarchical structure: The corridor level control acts in a supervisory capacity dynamically allocating traffic among alternative corridor facilities, including freeways, frontage roads, and signalized arterials. The local level control then selects control parameters for the individual facilities based on the predicted usage at the corridor level. A user specified performance function is optimized in the process. Both recurrent and nonrecurrent congestion scenarios were simulated using the SCOT model as a test bed. It is shown that, in most cases, significant benefits in performance can be obtained when the system operates as designed.

Federal‐Aid Highway Policies Affecting Utilities

After the passage of the 1956 Federal‐Aid Highway Act, the Bureau of Public Roads of the U.S. Department of Commerce and the state highway departments recognized that the control of access could be materially affected by the extent and manner in which publicly and privately owned utilities cross or otherwise occupy the rights of way of interstate highways. The Bureau of Public Roads considers the accommodation, adjustment, relocation, or installation of utilities as being associated with a development program that will bring great benefits to the general public and all its varied interests. Therefore, in recognition of the need for establishing a uniform policy on the accommodation of utilities, the American Association of State Highway Officials (AASHO) Committee on Planning and Design Policies began the task of developing such a policy in the fall of 1957. After long debate and discussion, and many meetings with national segments of the utility industry, including representatives of AWWA, “A Policy on the Accommodation of Utilities on the National System of Interstate and Defense Highways” was approved by letter ballot of the states and adopted by AASHO on July 30, 1959. On September 30, 1959, the policy was accepted by the federal highway administrator for use on federal‐aid interstate projects. The policy permits no utilities along interstate highways on new location and requires the removal of utilities that might exist along such highways where they cannot be serviced without direct access from the through‐traffic roadways or ramps. It permits utilities along frontage roads and across interstate highways, all in such manner that they can be serviced without direct access from the through‐traffic roadways or ramps.