United States Department of Transportation
i
Ultra-Violet Headlamp Technology for Nighttime Enhancement of Fluorescent Roadway Delineation and Pedestrian Visibility
-
1998-01-01
[PDF-59.27 KB]
Details:
-
Alternative Title:Ultraviolet Headlamp Technology for Nighttime Enhancement of Fluorescent Roadway Delineation and Pedestrian Visibility
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Resource Type:
-
Geographical Coverage:
-
Corporate Publisher:
-
Abstract:Safety on the roadways at nighttime has been a major concern for many years. Motorists driving at night are 2 to 3 times more likely to be involved in an accident at night than during the daytime. About half of the motor-vehicle deaths occur at night; however, death rates based on mileage are about four times higher at night than during the day (1). Nighttime driving is especially frustrating to the older population. The American Association of Retired Persons surveyed 1,400 of their members, and over half of the respondents indicated that they drive less at night due to reduced visibility and problems with glare (4). Detection of traffic control devices and hazards on the roadway is an essential part of safe driving. It has been shown that at night most drivers tend to overdrive their low beam headlights and operate at very short preview times, which could possibly explain the increase in accidents (5). Researchers have investigated ways of making objects and pedestrians more visible at night, thus increasing their preview time for drivers. There is a current FHWA effort to evaluate the use of ultra-violet lighting in conjunction with low beam headlights to provide increased nighttime visibility. Although the concept of ultra-violet headlamps has been in existence for some time, a new ultra-violet (UV) lamp technology developed in Sweden has given researchers new insights into the possibilities of its use. The prototype UV headlamps configured similarly to high beam headlamps and are intended for use with fluorescent traffic control devices. The headlamps emit UV radiation in the spectral range of 320-380 nm, which is invisible to the human eye. The short wavelength light emitted by the UV headlamps reacts with the fluorescent properties of objects it comes into contact with to produce long wavelengths of light or visible light. In order to improve the visibility of pavement markings, the markings would have to include a fluorescent component. The UV headlamps could potentially offer high beam performance of headlights without glare. The pavement markings used in the current study were all thermoplastic; however, fluorescent pigments or dyes could also be added to the more common painted markings. The fluorescent thermoplastics markings are more than double the cost of conventional thermoplastic markings; however, fluorescent paint markings are expected to cost less than 10% more than their conventional counterpart. The UV headlamps would always be used with the existing low beams, and it is not anticipated that the high beam units would be removed.
-
Format:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type:
