Andre, this may be for you....something I have wondered over time. Grew up in 69th, 77th garage territory and saw certain GM buses 1081, 7606, 7647 7741 (possibly 7431, 7656 and a couple in the 9000-9599 group) delivered with mid- shift marker lights on both sides of the bus, which were yellow instead of red. I'm referring to the marker lights over the left-side center window and the right-side rear exit doors. They appeared to have the yellow lens normally used on turn signals. With those, the bus could be seen for blocks at night. I always thought it was a cool "oddity" which set them apart from other buses in their respective series. They retained the feature for the life of the vehicle, through the "Ultimate Fleet Maintenance" rehabs. I don't recall any in the 9600-9799 group and I have never found any posts or notes on them. Any thoughts?