(1) In addition to the rules for longitudinal occupancy, the following shall apply to new aerial crossings:

(a) consideration shall be given to minimizing the frequency and length of crossing spans.

(b) facility crossings shall be made as nearly as possible at right angles to the highway.

(c) installation shall comply with the current edition of the National Electric Safety Code, or other appropriate code or regulation. 6.4008 meters (twenty-one feet) of clearance is required above the surface of the roadway.