The quality of motorist information systems is of considerable importance to the safety and efficiency of our Nation's highways. Accordingly, the Federal Highway Administration continues to be engaged in a number of activities that pertain to improving highway signing. For example, real-time information systems are now the subject of intensive research and development efforts by the Office of Research. Modern technology now permits communication of real-time information to drivers by means of variable message displays. Thus motorists can be given advanced warning of freeway incidents or other prevailing conditions such as fog or icy roads. In other words, real-time variable message signs provide the capability of giving the driver timely and useful information which corresponds to changing traffic conditions. Examples of major types of such signs are rotating drums, matrix lights, matrix discs, rolling screens, blank out incandescent, neon and fluorescent lamps signs, and new fibre optics signs.