(a) General rule.--The department on State-designated highways and local authorities on any highway within their boundaries may erect official traffic-control devices, which shall be installed and maintained in conformance with the manual and regulations published by the department upon all highways as required to carry out the provisions of this title or to regulate, restrict, direct, warn, prohibit or guide traffic.

(1) Local authorities shall obtain approval of the department prior to erecting an official traffic-control device on a State-designated highway except where department regulations provide otherwise.

(2) Local authorities shall obtain approval of the department prior to erecting any traffic signal except in a municipality with a traffic engineer qualified in accordance with department regulations.

(b) Standards for department approval.--The department shall promulgate rules and regulations setting forth minimum standards and factors to be considered in determining whether approval shall be given by the department for the installation and maintenance of official traffic-control devices. The factors shall include, but not be limited to, the volume of traffic and the number of accidents that occurred in each of the three preceding years.

(c) Agreements to waive department approval.--The department may enter into agreements with local authorities transferring to them the authority to install official traffic-control devices without specific State approval provided they conduct traffic and engineering investigations which conform with the rules and regulations promulgated by the department.

(d) Signals on municipal boundaries.--Whenever the need arises for the installation of a traffic-control signal on or near the boundary of two political subdivisions adjoining each other so as to be beneficial to both, either may petition the department for authority to install the signal. If the political subdivisions cannot amicably agree upon an allocation of the costs of installation and maintenance of the signal, either may petition the court of common pleas of the county in which the traffic-control signal is to be installed within 90 days after receiving the approval of the department and the court shall determine the proper allocation of the expenses to be incurred. The political subdivision that originated the request to the department shall install the traffic-control signal within 90 days of the date of the court order or of an amicable agreement between the political subdivisions.