Del. Code tit. 22 § 706
This chapter shall not abridge the powers of the city council or the town commissioners of any town or any other municipal officer in regard to public ways or parks in any manner except as provided herein, nor shall they authorize the taking of land or the laying out or construction of a way or a park or the alteration, relocation or discontinuance thereof, except in accordance with the laws governing the same; provided, that after an incorporated city and/or town has adopted an official map under this chapter no public way shall be laid out, altered, relocated or discontinued if such laying out, alteration, relocation or discontinuance is not in accordance with such official map as it then appears, unless the proposed laying out, alteration, relocation or discontinuance has been referred to the planning commission of such city or town established under this chapter and such planning commission has reported thereon or has allowed 45 days to elapse after such reference without submitting its report. After a city or town has adopted an official map under this chapter, no person shall open a way for public use, except as provided under the sections of this chapter, unless the location of such way is in accordance with the official map as it then appears or has been approved by the planning commission established under this chapter, and, in either case, the grading, surfacing and draining of such way have been approved by such commission or by the city or town engineer.
22 Del. C. § 706