1993 Buick Century Owner's Manual - Page 139
1993 Buick Century Manual
Page 139 highlights
Shape of Road Signs The shape of the sign will tell you something,too. r x Y - An OCTAGONAL (eight-sided) sign means STOP.It is always red with white letters. A DIAMOND-SHAPED sign is a warning of something ahead-for example, a curve, steep hill, soft shoulder, or a narrow bridge.
We apologize, but we cannot currently deliver this PDF manual by request of the manufacturer.
We apologize for any inconveniece.