23 CFR § 950.7 - Interoperability requirements.
(a) For any toll facility operating pursuant to authority under a 1604 toll program, the toll agency shall -
(1) Identify the projected users of the facility;
(2) Identify the predominant toll collection systems likely utilized by the users of the facility; and
(3) Identify the noncash electronic technology likely to be in use within the next five years in that area.
(b) Based on the identification conducted under subsection (a), the toll agency shall receive the FHWA's concurrence that the facility's toll collection system's standards and design meet the requirements of this part.
(c) In requesting the FHWA's concurrence, the toll agency shall demonstrate to the FHWA that the selected toll collection system and technology achieves the highest reasonable degree of interoperability both with technology currently in use at other existing toll facilities and with technology likely to be in use at toll facilities within the next five years in that area. The toll agency shall explain to the FHWA how the toll collection system takes into account both the use of noncash electronic technology currently deployed within an appropriate geographic area of travel (as defined by the toll agency) and the noncash electronic technology likely to be in use within the next five years in that area. FHWA, in determining whether to concur in the toll agency's proposal, will give appropriate weight to current and future interoperability with toll facilities in that area. The facility's toll collection system design shall include the communications requirements between roadside equipment and toll transponders, as well as accounting compatibility requirements in order to ensure that users of the toll facilities are properly identified and tolls are charged to the appropriate account of the user.
(d) A toll agency that operates any toll facility pursuant to authority under a 1604 toll program must upgrade its toll collection system to meet any applicable standards and interoperability tests that have been officially adopted through rulemaking by the FHWA.
(e) With respect to facilities that are tolled pursuant to the Value Pricing Pilot Program, this part only applies if tolls are imposed on a facility after the effective date of this rule. However, such facility is subject to this part if the facility's toll collection system's method or technology used to collect tolls from vehicle operators is changed or upgraded after the effective date of the regulations in this part.
(f) Nothing in this part shall be construed as requiring the use of any particular type of electronic toll collection technology. However, any such toll collection technology must meet the interoperability requirement of this section.