In this Act, except where the context otherwise requires, "highway" means the whole or a part of a highway other than a ferry or waterway.
Where a highway passes over a bridge or through a tunnel, that bridge or tunnel is to be taken for the purposes of this Act to be a part of the highway.
In this Act, "highway maintainable at the public expense" and any other expression defined by reference to a highway is to be construed in accordance with the foregoing provisions of this section.