It's a pretty safe bet that there will not be ground vehicles in FO4. VANS shows you a path to your objective in VATS, nothing more. Glad to put your mind at ease 馃槃

Bethesda has confirmed that Fallout 4 will not have vehicles, other than the Vertibirds.

There could well be an association with the actual Vault-Tec vans found in the game world, perhaps for restocking vital items such as weapons, ammo, or stimpaks. The color of the van seen in the icon portrays it as being some kind of emergency vehicle, which would make sense in this particular context. In essence, there may be a way that the perk is able to direct us to any VT vans in the vicinity as an additional function.

EDIT: the first one we see in the tutorial is parked across the road from the player's house, and the second one is near to the entrance to Vault 111. Although the first has clearly been moved when we arrive back at Sanctuary Hills, the second one can still be seen as we exit the vault.