||The Salt Lake Metropolitan Area, like many national urban areas, is faced with a transportation problem generated primarily by the readily available automobile in urban movement situations. This general availability has allowed for the development of a local urban form perpetuating an undesirable automobile dominance. This automobile oriented urban form, while complementing automobile use, has decreased the effectiveness of alternative modes of transportation. People who rely heavily upon these alternative modes for their urban mobility find themselves facing serious noncompetitive positions with respect to their social, economic, and physical welfare. These people then are classified as captive riders. While recognizing the complexities of urban transportation problems, the focus of this these is aimed at providing a guide allowing for the structuring of the Utah Transit Authority's system so as to efficiently service its captive rider population. Thus, the purpose of this thesis is to analyze and predict the distribution of areas within Salt Lake County that have high numbers of their populations exhibiting transit rider characteristics. Salt Lake County's urban form precipitating from the automobile domination manifests itself in many ways, each acting in opposition to efficient mass transportation. Leap-frogging suburban development, decentralized land use, subdivision design, and inadequate residential population densities have contributed greatly to the 60 percent drop in patronage and the 38 percent drop in local transit service since 1960. These factors as well as prevailing social stigmas, patron behavioral patterns, and operational financing problems tend to limit the potential that the Utah Transit Austerity has for implementation of a full scale mass transit program or even expansion of service aimed at extensive patronage increases. A mass transit survey conducted in May 1970 not only proved the hypothesis that a limited transit system, such as the one in Salt Lake City, is patronized mainly by the captive riders; it also identified the demographic characteristics of the riders. Paramount among these characteristics was the limited availability of automobiles to the riders either because of their economic situation or physical limitations. From an analysis of the distribution of populations exhibiting these captive rider characteristics, the home origins and thus the highest optimum residential service areas are identified. The residential service area analysis reveals that the populations occupying areas around the Central Business District (CBD) have the highest captive rider characteristics; thus, this area will benefit greatest from convenient mass transit service. Sugarhouse, South Salt Lake, Murray, and Midvale also combine to form significant regions occupied by existing and potential transit riders. The indices used in this analysis were the automobiles per dwelling unit, low annual income, and the population characteristics, age and sex. Identification of captive rider service areas not only involves the determination of rider home origins but also the delineation of their transit destinations or nonresidential service areas. The indices for this analysis centered around the identification of high employment and transit generating areas. In particular the factors used in this analysis were the following: commercial and industrial employment; generalized land use; and the identification of specific mass transit generating facilities. From the analysis of the above factors, three hierarchies of destination areas are identified. First and most important is the CBD and its associated commercial and industrial areas; second is the University of Utah and its surrounding urban area, the west Redwood Road/airport commercial zone, Kennecott-Bacchus operations, and the Sugarhouse area; third is State Street south to Midvale and the two regional shopping malls. The populations occupying the regions identified by the service area studies must be the recipients of a program aimed at concentrating the available transit services. Only after these captive rider populations are adequately serviced will attempts at extensive system improvements by accepted by both the population at large and the legislative officials.