The term security policies is a slight misnomer. It is also known under a more accurate term of Extensible Data Security (XDS). It is an evolution of record-level security that was deprecated from AX 2012: you could still do this, but it wasn't a recommended approach.
In this scenario, we will create a policy that only allows access to vehicles of the truck type. We will have a team that only has access to trucks when creating service orders.