Our 1960 population census will procure the first nationwide data on place of work and method of travel to work. In view of the widespread theoretical and practical interest in commuting, serious consideration must be given to the types of research for which these new data will be appropriate, and to alternative sources of information. This paper compares and contrasts census data on commuting with the information derivable from traffic studies and management records. It illustrates their uses and weighs the relative merits of the three sources for different types of study, and shows that each source has a relatively unique research utility.