W21 Series — Workers and Equipment Warning Signs

The W21 Series includes warning signs that alert drivers to workers, equipment operators, and utility crews in or near the traveled way. These orange diamond signs are used wherever workers are exposed to traffic — at active excavation, equipment staging, utility operations, and shoulder maintenance. WORKERS (W21-1), SHOULDER WORK (W21-5), SHOULDER CLOSED (W21-5a), and UTILITY WORK AHEAD (W21-7) are commonly combined with the W20 Series advance warning to give drivers adequate advance notice of human presence near the roadway.