1993 Buick Regal Owner's Manual - Page 131

I i ? u RAILROAD ADVANCE CROSSING , - A - / Y NARROW BRIDGE LOW SHOULDER FLAGGER AHEAD WORKERS AHEAD 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 torn up. And there may be workers and maintenance vehicles around, too.