Past research has not addressed the specific procedures needed to esti
mate the total number of people traveling by motor vehicle in a state
or the number of vehicular trips they take based on a sample of those
travelers. Methods were developed in a study in which leisure traveler
s were surveyed enroute throughout a state over a year's time. Procedu
res involved in trip estimation are discussed, and a simple method for
cross-validating estimates obtained is proposed. An estimate of one s
egment of these trips was validated by comparing it with a figure obta
ined from a state agency, suggesting that the approach is sound. Impli
cations of the method and its results are discussed.