California Partners for Advanced Transportation Technology

A work zone (WZ) is visually confusing, and while no WZ looks like any other, they all share a common feature. All of them present an array of flashing light signals which are especially prominent at night. These signals ignite with no relation to one another. Each, by itself, is designed to be highly visible, attention-getting and salient, being positioned high on vehicles, along barriers and on other equipment. In this two-part study we investigated ways to make the overall visual appearance of a WZ more compatible with the needs of passers-by. The first part consisted of psychophysical tests to assess the effect on lane keeping ability when the WZ signals were ignited synchronously, as opposed to asynchronous ignition. The second part investigated the feasibility of using wireless communication to coordinate light ignition times and to create coherence among the warning lights. The feasibility of triggering the signals in sequence to create a visible pattern that is instructive to the passing driver was also considered.