Vehicles, visitors and contractors
A manned gatehouse controls and records every movement onto and off your site: deliveries checked against the schedule, contractors signed in and inducted, visitors issued and recovered, and vehicles checked where the risk calls for it.
For industrial and logistics sites that means weighbridge and delivery coordination alongside security. For construction it means contractor induction records that stand up when somebody asks for them.
Gatehouse officers work to written assignment instructions agreed with you, so the policy is consistent regardless of who is on shift, and incidents are logged in a form you can use.