What is an illegal practice under the federal odometer law?

Odometer tampering is considered an illegal practice under the federal odometer law because it involves knowingly altering or changing a vehicle's odometer readings to reflect less mileage than the vehicle has actually traveled. This action is deceptive as it misrepresents the vehicle's usage and affects its value significantly. The law is designed to protect consumers from fraud and ensure transparency in vehicle sales by mandating accurate odometer readings.

On the other hand, practices such as odometer calibration are conducted to ensure the accuracy of the odometer in accordance with set standards, and are legal as long as they are done properly and transparently. Regular maintenance simply involves routine servicing of the vehicle and does not alter odometer readings. Collecting and accumulating mileage information is typically part of many automotive business practices and is also legal, as it helps in assessing vehicle performance and comparing historical data without fraudulent intent.