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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
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Publication Number: FHWA-HRT-04-132
Date: December 2005
Enhanced Night Visibility, Volume I: Executive Summary
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CHAPTER 5—PAVEMENT MARKINGS
The pavement marking study (ENV Volume VIII) focused on the detection distances of three pavement marking materials: a liquid system, fluorescent thermoplastic, and fluorescent paint. The liquid system was chosen because it has approximately twice the retroreflectivity of conventional patterned tape markings. Fluorescent pigments were added to the other two pavement markings to evaluate the potential benefit of UV–A in these materials. The study included all of the visual performance studies' UV–A configurations and the two baseline headlamps types (HLB and HID) assessed alone. Three additional headlamp-only systems were also included for a total of 11 VES configurations. Thirty participants were divided equally among three age groups: younger (18 to 25 years), middle-aged (40 to 50 years), and older (60 years or older). While driving, the participants indicated when they could first detect the beginning of a pavement marking section after a blank section and when they could detect the end of a pavement marking section before a blank section. The participants performed this detection activity for each marking type using each of the VESs.
The results indicated that all the VESs provided adequate detection distance, but no pairing of VES and pavement marking outperformed the others enough to merit recommendation. The supplemental UV–A did not improve detection distances when paired with the HID or the HLB headlamps. This effect was likely caused by significant degradation of the fluorescent pigments in a short time period. None of the results of this study supported the additional cost of adding fluorescent material to pavement markings.