R.I. Gen. Laws § 42-17.10-4: Method of payment.

If the alleged violator elects to dispose of the charge without personally appearing before the traffic tribunal, the alleged violator shall execute the form indicated and return it to the traffic tribunal not later than twenty (20) days from the date of the summons either by mailing or delivering the form and summons to the violation section of the traffic tribunal, or to its designee, together with cash, check, or money order in the amount indicated by the fine schedule on the form.