Abstract
Dark adaptation and critical flicker fusion thresholds division of the minnesota highway department and a manufacturer of highway sign materials conducted a joint field study of an experimental reflectorized color guidance system installed in the cloverleaf interchange at the intersection of us 61 and minn 36. This is a report of the experimental results of traffic surveys and driver interviews made for the study. A description of the reflectorized system is included. /author/ during the summer months of 1959 the traffic and planning.