Author(s):
C. Pinnell, P.R. Tutt
Publication Date
1963
Abstract
Cooperative research by the Texas Highway Department and the Texas Transportation Institute has been directed toward a study of the various elements of urban freeways and the effects of these elements upon freeway operation. Two such elements which have been closely studied are frontage roads and diamond interchanges. The purpose of this paper will be to discuss the design and operational aspects of these elements and to develop criteria for their use.|Continuous frontage roads have been used extensively on urban freeways in Texas and a great deal of operational experience on freeways utilizing these elements has been obtained. Freeway studies have indicated that numerous advantages in system flexibility, capacity, operation, and construction have been obtained with this type facility. This paper will discuss these advantages and present supporting data obtained from freeway studies in Texas.|One early criticism of freeway sections with continuous frontage roads was that they tended to create problems in designing efficient interchanges. Diamond interchanges have been used almost exclusively in conjunction with the freeway-frontage road design, and operational studies indicate a very high degree of operational efficiency and capacity can be obtained with this type interchange.|A capacity analysis will be developed for the following three types of diamond interchanges: 1) Conventional two-level, 2) Split two-level, 3) Three-level.|The results of this analysis will indicate the wide range of interchange capacity that can be obtained with the three variations of the diamond interchange. The capacity analysis will also point out various design criteria of diamond interchanges that are necessary to obtain maximum operational efficiency and capacity.
Report Number:
62-3
Link(s):
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