92 Ill. Adm. Code 1535.333
Flashing Light Signals
Section 1535
Section 1535.333 Flashing
Light Signals
a) Unless the Commission otherwise specifically authorizes,
installations of light-type signals hereafter made for warning at grade
crossings shall be of the flashing light type.
b) Flashing light signals shall conform generally as to aspect
with that shown in Appendix B, Illustration E. Special conditions such as
those presented by dual lane highways, streets with more than two traffic
lanes, crossings with an unusual arrangement of tracks, etc., may require
cantilever or other special mountings or supports. Individual approval by
appropriate order or resolution of the Commission must be obtained in each
special case. Application for such approval should be made on Form 3.