Abstract
This additional article, to a main paper on the issue of electronic toll collection (ETC) in Puerto Rico, considers the functions of the technologies in other vehicle-roadside communication purposes. This includes parking, in particular the operation of charges; traffic management; commercial vehicle operations (vehicle checking) and congestion pricing with variable tolls at different times of day. The applications are currently seen as secondary to the main objectives behind ETC deployment but may become more important in the future.