Different cities often have dramatically different mobility pricing and rules, so its important to specify what region certain operations are occurring in; Passport uses a common “zone” concept to deliniate regions for all products.
A zone is a region where parking can be purchased and enforced; zones are defined by individual cities and accessible through Passport’s APIs for both creating sessions and enforcing against them.
In the case of zone retrieval, any individual zone number is not guaranteed to be globally unique, so providing location information to when retrieving zones can ensure you only retrieve relevant zones. This location information can be thought of as a geographic filter.
Zones have both a
zone_number; the former is machine-readable and globally unique and the latter is human-readable and regionally unique. Zone numbers are commonly represented on on-street signage.