Del. Code tit. 23, § 2306

In addition to any other powers of arrest, any law-enforcement officer is hereby authorized to arrest without warrant any person who the officer has probable cause to believe has violated the provisions of this chapter, regardless of whether the alleged violation was committed in the presence of such officer. This authority to arrest extends to any hospital or other medical treatment facility located beyond the territorial limits of the officer’s jurisdiction provided there is probable cause to believe that the violation of this chapter occurred within the officer’s jurisdiction. This authority to arrest also extends to any place where the person is found within 4 hours of the alleged operation of a vessel if there is reason to believe the person has fled the scene of an accident in which the person was involved, and provided there is probable cause to believe that the violation of this chapter occurred within the officer’s jurisdiction.