The most common methods involve RFID transponders (tags) placed in vehicles that communicate with roadside readers. For vehicles without transponders, Automated Number Plate Recognition (ANPR) cameras capture their license plates, and bills are typically mailed to the registered owner.

Most ETC systems have robust violation enforcement mechanisms. If a transponder is not detected and the license plate cannot be read (e.g., obscured, foreign plate), a violation process is initiated, which may involve manual review of images or specific enforcement procedures.

Absolutely. ETC technology is the foundational element for implementing congestion pricing, distance-based road user charging (RUC), or time-of-day specific tolls. The system's ability to identify vehicles and track their movements allows for highly flexible and nuanced charging policies.

For authorities, key benefits include significantly reduced operational costs (less need for toll booth personnel), increased revenue efficiency, improved data collection for traffic analysis and planning, and the ability to implement more sophisticated and equitable pricing policies.