The period of economic expansion and affluence since World War II created a strong tendency to base planning on unquestioned extrapolation of past trends. This method is acceptable in areas where the developmental trends are in desirable directions. But when this is not the case, this method does not represent rational planning, since its effect is to continue and encourage undesirable developments. Urban transportation has suffered greatly from this type of planning; many of our national and metropolitan area transportation studies placed a heavy reliance on .continuation of growth in auto ownership, VMT's, decentralization, etc. They failed to set clear goals for public transportation and standards for its service.