R.I. Gen. Laws § 42-13.1-5: Collection of tolls on passenger cars and other vehicles expressly prohibited.

Notwithstanding any other provisions of this statute, the department is expressly prohibited from collecting tolls hereunder on other vehicles, herein defined to include motorcycles, passenger cars, and all other vehicles classed one through seven (7) pursuant to the Federal Highway Administration (FHWA) vehicle classification schedule.