Increasing visual complexity in the roadway environment is making the task of driving a greater challenge for the motorist. Recent advances make it possible to produce fluorescent retroreflective materials suitable for long-term outdoor signing applications. This article presents the results of a field study investigating the relative advantage of fluorescent colors over standard colors for detection, color recognition, and conspicuity against a complex dark background. These fluorescent retroreflective materials are detected with higher frequency, and recognized with greater accuracy at further distances than the corresponding standard highway colors. They also have greater attention-getting properties (more Conspicuous) during daylight than the corresponding standard highway colors. The luminance contrast ratio of the sample to the camouflage background appears to correlate with the visibility/conspicuity results obtained in this study, particularly within a given color series.