Gore Area. Gore areas of trumpets, diamonds, and exteriors of loops adjacent to the
exit point should be graded to obtain slopes of 6:1 or flatter, which will not endanger a
vehicle unable to negotiate the curvature because of excessive speed.
Trumpet Interiors. Interior areas of trumpets (Fig. 2.24) should be graded to slopes
not in excess of 8:1, sloping downward from each side of the triangle to a single,
rounded low point. Roadside ditches should not be used. Exteriors should be graded in
accordance with mainline or ramp standards.