Cold Shoulder

The side of a road’s called a shoulder, but why?
The resemblance, to me, isn’t striking.
The berm or the edge, a more literal choice,
Would be, somehow, much more to my liking.

I enjoy a good metaphor when apropos
But in this case I’m driven to wonder
Why not elbow or ankle or even an ear –
All could help to keep stop lanes asunder.

Who came up with this phrase? Not a bureaucrat, no.
Maybe somebody clever with wordin’
And because of his efforts, we’re left, to this day,
With the need to thus shoulder the burden.