Measurement of travel times provides a critical component, along with traffic volumes, in the calculation of traffic congestion. This paper describes the results of extensive field tests of several methods used to calculate travel times. In particular, the paper examines the use of Hi- 8 mm video cameras (camcorders) and an automatic license plate reading system, based on machine vision technology, to perform travel time calculations. The paper presents the preliminary results of field trials conducted in Boston, Mass., Seattle, Wash., and Lexington, Kentucky. Besides the results of the surveys, the paper examines issues related to transferring this new technology to this application. The paper looks at the logistics of conducting extensive surveys, lessons applicable to survey design, and the quantity and statistical significance of the data required. A comparison is made between the application of machine vision to traffic surveys with other applications of machine vision to the transportation industry. It also presents future plans for the use of machine vision for the measurement of various traffic parameters.