Cutting off corners of diamond-shaped signs when mounted on a barrier wall

Kentucky Transportation Cabinet has cut the corners of signs mounted on barrier walls in a few situations over the years. This practice was certainly not desirable, but necessary in order to dual-mount the signs.
One situation is in very tight lane restrictions when signs have to be mounted on a barrier wall. The I-264 Watterson Expressway widening in Louisville and the I-75 widening in northern Kentucky, for example. Both projects required traffic to be maintained in narrow lanes running close to the barrier wall. The engineer decided it was more important to have the signs, with the corners cut, than to either not have the signs or to use less effective, small signs. No standard, policy, or practice exists. It is left to the engineer to decide on a project-by-project basis.