Del. Code tit. 17 § 176
The Department may designate and establish controlled-access highways as new and additional facilities or may designate and establish an existing street or highway as included within a controlled-access facility. The State or any of its subdivisions shall have authority to provide for the elimination of intersections at grade of controlled-access facilities with existing state and county roads and city or town streets by grade separation or service road or by closing off such roads and streets at the right-of-way boundary line of such controlled-access facility; and after the establishment of any controlled-access facility, no highway or street which is not part of said facility shall intersect the same at grade, except as a temporary expedient, for which a separate resolution for each individual location shall be approved by a duly executed resolution of the Department. No city or town street, county or state highway, or other public way shall be opened into or connected with any such controlled-access facility without the consent and previous approval of the agency having jurisdiction over such controlled-access facility. Such consent and approval shall be given only if the public interest shall be served thereby.
17 Del. C. § 176