Ford Motor Company surveyed Ford management personnel who drive Ford Motor Company lease vehicles. From the responses, in-use fuel economy data were computed on over 10,600 1978 model year cars. Analyses of the data are presented which include: fuel economy summary statistics; regressions of fuel economy ratings versus in-use fuel economy; measures of the ability of EPA ratings to rank in-use fuel economy; and the influence of car size class or transmission type on fuel economy regression and correlation. Wide ranges of fuel economies were found for each vehicle model type. The analysis shows no significant trend by car size class in the relationship between in-use fuel economy and metro highway fuel economy ratings.