Evaluation of an LPR-Based Toll Enforcement System on Portuguese Motorways

This paper presents an approach for evaluating video-based enforcement systems for motorway toll collection, which has been applied to the case of Portugal´s largest motorway operator, Brisa. The results of this evaluation have contributed to the design of a new LPR system, denoted advanced license plate recognition (ALPR), also described in this paper. The ALPR is currently being deployed not only by Brisa, but also by other operators that use the Via Verde system. A significant decrease in the need for human intervention has been an important improvement, in which the introduction of a tunable and trustable confidence level in the LPR process has played a key part