Evaluation of Pavement Edge Inset and Low Level Illumination Lights in Fog: Interim Report No. 1

About the report:

The Virginia Highway Research Council was asked to search for ways of making travel safer on fogbound highways. All literature obtainable on fog research was reviewed and after an in-depth review of fog abatement techniques it became apparent that neither technology nor hardware had advanced to the degree that it was feasible for highway usage. The literature did, however, suggest that two types of lights had potential for usage in fog. The types were: (1) Pavement inset lights for delineation of roadway (referred to as a lineal guidance system and unidirectional airport runway lights) and (2) lights mounted at low elevations for forward visibility. This finding was reported to Highway Department officials, who then requested that the Research Council obtain several of each type of light and set up an experiment to test the effectiveness of each. The pavement inset lights obtained were unidirectional airport runway lights 12 inches in diameter and weighing approximately 50 pounds. Each light carries a 200-watt bulb, and the intensity is variable. The low elevation lights are 500-watt, high intensity, quartz floodlights. The pavement inset lights were tested by placing them on the pavement surface in line with the edge line marking on each side of the road. They were tested by varying (1) the spacings between them and (2) their intensities. The testing, which was performed by a test crew and by professional members of the Research Council's staff, was cut short by the opening of the section of I-64 on which the lights were installed. After a review of the limited number of test results and consultations, a recommendation for spacing and intensities was made. It was recommended that a 1/2-half mile section of lights be installed in the eastbound lane of I-64 in Augusta County on Afton Mountain from milepost 27.90 to milepost 28.40. Daylight intensity of the lights will be 30% maximum and night intensity will be 10% maximum. At these intensities good delineation is afforded without undue glare. It has been adjudged that this 1/2-mile section is necessary to provide information for deciding whether the lights should be installed on the entire 6-mile section of I-64 spanning Afton Mountain. In the event that the 6-mile section is recommended at a later date the design of this half-mile section will be compatible and this shorter installation can be connected directly to it. No results or recommendation are included for the low-level illumination lights since not enough testing has been performed to allow any valid judgment on their effectiveness.

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