Note 3 to T300.5 is about access to terminations and splices. Why are you requiring access to it at each end of the culvert?
300.5(D)(1) is for direct burial cables. OP hasn't said boo about what is going to be in the PVC.
If you're using this as an argument, then all I need to do is bury one end of a 500-foot run of PVC raceway 1" below grade, and lay the rest on top of the ground and say "It's emerging from grade".[/quote]
Note 3 is in the NEC for the purpose of when raceways(conductors in raceways) are rising out of the ground to allow the raceway to rise up past the minimum burial depth without being a violation of the required depth. Such as a PVC installed from the house underground to the detached garage and then emerge from grade outside the detached gararge and run up the side of the bulding to say...an LB.
Raceways are permitted to be run laying on the surface of the grade as long as they are protected from physical damage, if the need to protect from physical damage exists.
Once a raceway is buried, one has to follow Table 300.5 for the burial depth.
As the raceway (enclosure) emerges from grade, it is required to be protected from physical damage as described in different methods of the NEC.
One could lay the PVC inside the culvert. As it emerges from the culvert, it can transition into the ground and run under the surface (as per Table300.5) to its destination. Of course protection of the PVC where needed should be provided.
