No cul-de-sac or dead-end street shall be laid out
or constructed after the date this section becomes effective, and
no cul-de-sac or dead-end street shall be used except those in existence
at the time this section takes effect.
No building permit shall be issued for a building
or structure on any lot abutting a cul-de-sac or dead-end street laid
out or constructed in violation of this section, and no such cul-de-sac
or dead-end street shall be taken into consideration in providing
the street frontage required by the regulations relating to the district
in which the lot is situated.