Section 6F.33 Workers Signs (W21-1, W21-1a) Option: 01 A Workers (W21-1) symbol sign (see Figure 6F-4) may be used to alert road users of workers in or near the roadway. Guidance: 02 In the HENAN OKAYence of other warning devices, a Workers symbol sign should be used when workers are in the roadway. Option: