This is the bed of a portion of the Roman Road that ran from Jerusalem to Gaza (compare the story of Philip in Acts 8:26ff).
This is a portion of the road that ascends out of the Elah Valley and that leads to Jerusalem. Note the “steps” that are carved in the bedrock as well as the “curbing” on both sides of the road. This is not actually how the road appeared when it was in use. In fact sand and fine gravel were placed over the steps, and paving stones on top of the sand so that the ascent was actually relatively smooth and traffic traveled on top of the paving stones.