The solution to metropolitan transportation problems should be sought through a continuing comprehensive planning program. The current (as of 1965) transportation problems that have resulted from urban sprawl, expanding population, and increased use of the automobile are becoming more difficult to solve. The problem may be brought into sharper focus by recognizing the need for more research and study for the smaller metropolitan areas that contain 41% of the nation's urban population. Four areas are recommended for additional study and research: (1) The use of the vertical dimension of air space above existing transportation rights-of-way; (2) the use of the time dimension for the reorientation of activities to reduce peak-hour traffic loads; (3) the design-year concept; and (4) the advanced acquisition and reservation of rights-of-way. The application of these findings to long-range comprehensive planning and programming will greatly assist the urban and transportation planner in solving the metropolitan transportation problem of the future.