What is the symbol on a worker ahead sign?

I hope this is the correct place for this type of question.

I was wondering what the symbol on a US DOT W21-1a Worker Ahead road sign is.

My wife thinks it's a flagger with their flag down. I think it's a person digging.

Unfortunately, even though I can find everything else, including the dimensions of the image, I can't locate a description of what the image is supposed to be doing.

This is the image for reference:

Official source please, if possible.

usa road-signs

Best Answer

Its a person digging. Its based on the UK roadsign by Margaret Calvert (who inspired roadsigns across the world - see the German or Australian ones for the same).

She is on record as saying she wished she'd made the sign more shovel-like.

She told Frieze: “I now regret that I didn’t put a corner of a spade on the ‘men at work’ sign, it would have stopped all the jokes about a man struggling to put up an umbrella!”

I guess its a salutary lesson about design, if its not 100% clear, its going to be confusing for all of future history!