What does this street sign (symbol) mean??

Question

What does a sign with a symbol (as described below) stand for/mean?

The sign is diamond shaped, showing three dashed lines up the center with a line on either side. The side lines are straight, then curve in, then are straight again. The whole thing resembles almost an open hourglass figure.

Thanks! Sorry I don't have a picture.

Answer 1

That sign just tells you that the road narrows ahead and/or tells you that there's no shoulders on the side of the road up ahead.

Answer 2

Narrowing lanes ahead.