What effect does transportation have upon a city's growth? This study addresses the question of how to predict changes in urban form caused by changes in transportation system characteristics. Two primary dimensions of urban form are considered: (1) composition--a shift in distribution of developed land-use patterns; and (2) extent--spatial growth characterized by conversion of undeveloped land and by expansion of the physical boundaries of urban areas. A multiple regression model is developed to measure changes in land use and value and to relate these to changes in transportation system service characteristics. Possible applications of the model are considered in terms of five important policy issues: (1) providing a feedback mechanism for land-use forecasting; (2) estimating accessibility of specific community groups to urban resources; (3) assessing changes in land value due to transportation system changes; (4) matching transportation configuration to desired urban distribution; and (5) improving coordination of federal urban policies. 29 pp.