Del. Code tit. 21, § 406

If no agreement, arrangement or declaration is in effect with respect to another jurisdiction as authorized by § 401 of this title, any vehicle properly registered or licensed in such other jurisdiction, and for which evidence of compliance is supplied, shall receive, when operated in this State, the same exemptions, benefits and privileges granted by such other jurisdiction to vehicles properly registered in this State. Reciprocity extended under this section shall apply to commercial vehicles only when engaged exclusively in interstate operations.