Abstract
A study conducted to find the need for improving delineation in construction zones with long-term lane closures or diversions is described. The need for improved delineation was established through two means a. a committee of traffic, construction, design, research, and specifications engineers and b. positive guidance, a technique that develops improvements to the highway information system from the driver's viewpoint. Once the need was established, improved delineation concepts were developed and tested in actual construction zones and evaluated for efffects on traffic performance and driver visibility.