New Jersey Statutes Title 54. Taxation 54 § 39A-6

The amount of motor fuels used in the operations of any user within this State shall be computed to be such proportion of the total amount of such motor fuels used in the user's entire operations within and without this State as the total number of miles traveled within this State bears to the total number of miles traveled within and without this State. Every qualified motor vehicle operated by the user may be equipped with an accurate mileage recording instrument in good working order, as prescribed by the director, and its reading shall be taken and recorded at such intervals as the director shall prescribe.