No, tickets are not required as it is a publicly accessible historical structure.
No, you cannot buy tickets on site for the Historic 's-Hertogenbosch Bridge (Drongelen Lock) because no tickets are required for entry. The bridge and associated lock structure are part of the public infrastructure and are freely accessible to view.
There is no visitor center, ticket booth, or staff on site to manage admissions. Visitors can simply approach the bridge and observe it from public vantage points. This open accessibility means that a visit can be spontaneous without prior planning for purchases.