(a) The department may enter into an agreement with one or more persons to provide, on terms approved by the department, personnel, equipment, systems, facilities, and services necessary to operate a toll project or system, including the operation of toll plazas and lanes and customer service centers and the collection of tolls.
(b) A person that enters into an agreement with the department to provide services for a customer to pay an amount on an electronic toll collection customer account at a location other than a department office may collect from the customer a service charge in addition to the amount paid on the account.

(c) The commission by rule shall set the maximum amount a person may collect as a service charge under Subsection (b), which may not exceed $3 for a payment transaction.