Abstract
The great mileage of multiple-lane high-speed freeways requires the mounting of directional signs over the roadway itself for the proper control of traffic. This is especially true at exit ramps of interchanges in order that traffic may have sufficient advance warning to position itself in the proper lane to make the desired movement. The number of installations makes it desirable that nationwide specifications covering the design and construction of these supports be revised as new research and development dictates this necessity.