[WorldMaker]

Not mechanic as in the person that services brakes, but Mechanical Engineer as in the person engineering them.

Mechanical Engineers in the US are usually expected to be Professional Engineers (professional license) and in good standing with ASME, the American Society of Mechanical Engineers (professional society).

[DaveExeter]

I dunno. I think only a tiny fraction of people with mechanical engineering degrees become Professional Engineers.

It's mostly Civil Engineers who bother to get PEs.

[Eddy_Viscosity2]

The people who need the P.Eng. qualification get it and the ones who don't need it tend not (why do all that extra effort if its not required). So that just means more civil engineering positions require it than mech eng positions.