6.—(1) Vehicles belonging to and used for official purposes by the Defence Forces and the Garda Síochána, and fire brigade vehicles and ambulances shall be exempt from payment of tolls.

(2) In this section—

"ambulance" means a mechanically propelled vehicle which is outwardly identifiable as and is used exclusively for the carriage of sick, injured or disabled persons;

"fire brigade vehicle" means a mechanically propelled vehicle used for the purpose of fire-fighting or rescuing persons or property from danger or for both such purposes.