1993 Buick Park Avenue Owner's Manual - Page 163

h I RAILROAD ADVANCE CROSSING W NARROW AHEAD BRIDGE LOW FLAGGER SHOULDER AHEAD W YELLOW indicates a general warning. Slow down and be careful when you see a yellow sign. It may signal a railroad crossing ahead, a no passing zone, or some other potentially dangerous situation. Likewise, a yellow solid line painted on the road means "Don't Cross.'' ORANGE indicates road construction or maintenance. You'll want to slow down when you see an orange sign, as part of the road may be closed off or tom up. And there may be workers and maintenance vehicles around, too.