The slope behind the shops

The pavement was narrow, leaving little space beside the advertising board. It was uneven where the roots of a tree had lifted the slabs. We measured the gap and photographed the surface before moving to the next street. I knew this route as a shortcut and had never thought of recording it. Travelling with someone who used a walking frame changed which details seemed important, even though nothing about the street itself had changed overnight.

From the passage, select two words or phrases that describe features of the pavement that could make access difficult.