It was a customs-duty tax on all incoming and outgoing goods in land and sea frontiers in addition to other inland ports.
Collecting was of greater concern to the procurators of Lugdunensis than to the other Gallic provinces as Lugdunum (now Lyon, France) was the main trading hub of the region.
[3] The bureaucracy surrounding the Quadragesima Galliarum grew in size and complexity over the centuries.
[4] Epigraphy associated with the tax shows the presence of a procurator and staff including: tabularii, a vilicus, and vernae.
The locations of these stationes have a pattern of being in ports and key mountain routes.