Driving miles estimates by teen drivers: how accurate are they?

The objective of this study was to determine how accurately teens can report miles driven. Participants were 118 drivers in Connecticut (average age 17(1/2) years; average time licensed 11 months). Half had their own vehicle; half shared family vehicles. Teens completed a telephone survey about their preceding week's driving, then completed a daily trip log for the next week and a second survey about the details of the logged week's trips and miles. Teens with their own vehicle provided odometer readings. Summing the miles for every trip was generally consistent with estimates from odometer readings. Overall mileage estimates were 20-30% lower than those from trip-by-trip listings, except for very low estimates for the first week by teens who shared vehicles. The results indicate that single overall estimates frequently understate total miles driven, but that prompted reviews of each trip can provide valid and detailed information.