Section 147 - Authority to establish standards for traffic-control devices(a) The Department shall adopt a uniform standard for each type of traffic-control device to be used on all highways open to the public in this State. Such standard shall correlate with, and so far as practical, conform to the standards used in other states.(b) The standards shall be recorded in a manual to be known as the Delaware Manual on Uniform Traffic-Control Devices for Streets and Highways. The manual shall have separate chapters setting individual standards for signs, signals and markings.(c) Any traffic-control device erected in violation of the manual, except experimental devices erected by the Department, shall be unofficial, unauthorized and unenforceable.(d) A person or corporation shall not sell or offer for sale in this State any traffic-control device or other device intended to regulate, warn or guide traffic unless it conforms with the state manual and specifications adopted under this section.60 Del. Laws, c. 701, § 3.;