Crossing state lines, with parts

If you're a class a driver carrying/hauling a load you're correct a private citizen be a no on that. It's all about unlawful search and seizure. It's all about knowing your rights, maybe it's different on the east side of the country but here on the west side of the country my glove box is locked so the trunk in the back and I know my rights so you'll need a warrant for that.

You were referring to a U-Haul truck. A DOT cop can make you open the back door, he would need a warrant to search it, but not to look. It isn't search and seize, it's just inspecting the load.

The DOT laws are federal laws BTW, not state.