Urban transportation studies have collected substantial data on land use, travel, transportation facilities and socioeconomic characteristics. It has been alleged that the collection of these data is excessively costly and time-consuming. In view of the evolving nature of the transportation planning process, a reexamination of data requirements and collection techniques has been needed. What data should be gathered in the future? What should be a transportation study's policy on data collection? In the research reported here, five representative transportation studies were examined in detail to reveal the kinds of data needed, to determine the costs of data collection, and to check the degree of use of the collected data. 4 related kinds of planning (comprehensive metropolitan land use planning, highway route selection, transit planning, and topics) were examined to determine the relationships of their data requirements to those of the transportation planning process.