Open road tolling (ORT) or free-flow tolling is the collection of tolls on toll roads without the use of toll booths. An electronic toll collection system is usually used instead. The major advantage to ORT is that users are able to drive through the toll plaza at highway speeds without having to slow down to pay the toll. In some installations, ORT may also reduce congestion at the plazas by allowing more vehicles per hour/per lane. The disadvantage to ORT is the possibility of "leakage"; that is, "violators" who do not pay. Leakage may either be written off as an expense by the toll operator, or offset in part or whole by fees and fines collected against the violators.