Travellers crossing a border where checks were abolished still encounter queues. Several distinct mechanisms produce them, and only one involves checking who a person is.
Controls can be reintroduced temporarily
The rules permitting open internal travel also allow a state to reinstate checks for a limited period where it identifies a serious threat to public policy or internal security.
Notification and time limits apply, and extensions require justification, though in practice controls have been maintained on some frontiers over long periods through repeated renewal.
Where they apply, they resemble the checks free movement removed, and the queue that results is the ordinary consequence of stopping every vehicle.
People and goods follow different regimes
Free movement of persons and the customs treatment of goods are distinct arrangements, so a lorry may face inspection where a car does not.
Commercial vehicles carry documentation about cargo, and checks on that documentation occur at fixed points with limited capacity for parking and processing.
Where a border separates different customs territories, the goods check becomes substantial regardless of what applies to travellers in the same vehicles.
Police checks are not border checks
Authorities may conduct policing within a border area under national law, provided the checks are not equivalent in effect to systematic border control.
The distinction is legal rather than experiential, and a traveller stopped in a random check near a frontier encounters something that feels identical to a border check.
These operations are typically targeted at specific offences, and their intensity varies with current enforcement priorities rather than with the border arrangement itself.
Infrastructure creates most delay
Many crossings sit at bridges, tunnels and mountain passes where the road narrows, and the queue reflects the geography rather than any control.
Restrictions on heavy vehicles through tunnels and passes, including timed access and convoy systems, create scheduled bottlenecks entirely independent of frontier status.
Holiday traffic concentrates on the same routes at the same times, and the resulting queues are often attributed to border checks that are not taking place.
Carrier obligations move checks upstream
Airlines and ferry operators are required to verify travel documents before boarding, since they bear responsibility for passengers refused entry on arrival.
That shifts the check to the point of departure, which is why identification is requested for journeys within an area with no border controls.
The result is a system where documents are checked frequently but rarely at the frontier itself, and travellers reasonably conclude that open borders mean something narrower than they expected.