1993 Buick Century Owner's Manual - Page 137

A \ LOW SHOULDER WORKERS AHEAD FLAGGER AHEAD ORANGE indicates road constructionor maintenance. You'll want to slow down when you see an orange sign, as part of the roadm y be closedoff or torn up. And a there may be workers and maintenance vehicles around, too. GREEN is used to guide the driver. Green signs may indicate upcoming freeway exitsor show the direction you should turn to reach a particular place.