Signs shall not resemble, imitate or approximate the shape, size, signals or devices, form or color of railroad or traffic signs. Signs shall not obstruct or interfere with the effectiveness of railroad or traffic signs, signals or devices. No sign shall be erected, relocated or maintained so as to prevent free ingress to or egress from any door, window or fire escape; and no sign shall be attached to a standpipe or fire escape. No sign shall be placed so as to obstruct or interfere with traffic visibility, nor be lighted in such a way as to cause glare or impair driver visibility, upon public ways.