Roadside Warning

A sign on the side of the highway
Provoked my eyes to pop,
‘Cause what it said was “Prison near,
So kindly do not stop.”

Of course, we kept on driving
But man, it made me think
And wonder just how many men
Have bolted from the clink.

Envision those escapees,
In their old-time stripy suits,
Just lurking on the roadside
With the warden in cahoots.

For if inmates, as intended,
Are locked up in cells with bars,
Then why post a dire warning
To the hordes of passing cars?

It’s a puzzle so perplexing
Who knows what it’s all about,
But I’m sure all drivers question
How the prisoners got out.