Some in the toll industry use the terms "interoperability" and "reciprocity" interchangeably. While on a high level, this may be the case, the two are sometimes used to represent different faces of the same coin:
Interoperability - The ability of one toll agency to read transponders issued by another toll agency. This could be due to both agencies' using the same transponder and reader technology (such as is done by the E-ZPass® Group) or one of the agencies using multiprotocol transponder and/or reader technology (such as is done by North Carolina).
Reciprocity - The exchange of data and funds between toll agency back offices to allow customers of one toll agency to utilize toll facilities of the other toll agency using a single account. This typically involves the exchange of transponder white lists and transaction files, but can also include license plate white lists to allow for image-based toll processing.
The “Moving Ahead for Progress in the 21st Century Act” (MAP-21) as well as toll agencies' desire to provide improved levels of customer service and convenience has stimulated increased interest in interoperability and reciprocity. While there are several existing regional toll programs, there has been recent progress in cross-regional interoperability/reciprocity, as evidenced by the efforts between North Carolina and E-ZPass, North Carolina and Florida, and between Oklahoma and Texas.