Altering a vehicle’s odometer to show a lower mileage than that actually travelled is not itself illegal. However, the practice of selling a ‘clocked’ vehicle to someone, without notifying them that the vehicle’s mileage has been altered is illegal. Historically, this has been to increase the value of a vehicle, but many consumers are now adjusting their cars’ mileages to avoid excess mileage penalty fees that are part of a car’s finance agreement.