Effects of Chevron Alignment Signs on Driver Eye Movements, Driving Performance, and Stress

In China, the chevron alignment sign (a vertical rectangle with a white arrow and border on a blue background) has been widely used on roadway curves to provide advance warning and positive guidance through curves. Chevron alignment signs are retroreflective guidance devices installed near roadway edges indicating roadway alignment. But the effects of the China chevron alignment signs on drivers’ eye movements, driving performance, and stress have rarely been studied. Few guidelines have been established for the size and application of chevron signs in China. This paper reports on a driving simulator experiment that measured the data on drivers’ eye movements, inputs, and electrocardiograms through an urban expressway ramp with and without chevron alignment signs. A comparative analysis was conducted to examine the changes in drivers’ eye movements, driving performance, and heart rates. Results show that drivers pay more attention to the roadside near chevrons; they are also more relaxed and tend to drop their speed more when chevrons are present. This finding indicates that chevron alignment signs do provide advance warnings and positive guidance and make drivers tend to drop speed more through curves, which improves safety and uniformity in curve delineation on urban expressway ramps.