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Received Oct 12, 2017; Revised Mar 4, 2018; Accepted Mar 8, 2018
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1. Introduction
Glare is the visual effect of scattering light within the eye caused by a high brightness object or a strong contrast light source in the field of view [1–3]. Glare affects cognitive performance which in the visual periphery is more susceptible to disturbances, and discomfort glare impairs peripheral visual performance [4]. The presence of glare leads to a significant reduction in the safety margin and the number of traffic accidents is much higher in the glare conditions than in the nonglare conditions [5].
At night, the headlamps of an oncoming vehicle may cause harmful glare that interferes with the sight of drivers [6]. Installing antiglare facilities along the road is an economical and feasible method for solving the glare problem caused by the headlamps of oncoming vehicles. Traditionally, antiglare facilities on a concave vertical curve road are identical in height to those on a straight road, which follows the standard. This design often results in light leakage on concave vertical curve roads because the antiglare facilities are too short, causing the dazzling phenomenon. Thus, the height of the antiglare facilities must be designed based on different freeway alignments.
Previous studies mainly considered the relationship between driving safety and antiglare facilities. In order to block the road users’ view of activities that can be distracting, MUTCD recommends installing screen to discourage gawking and reduce headlight glare from oncoming motor vehicle traffic [7]. Drivers of heavy vehicle and light vehicle need different height of anti- dazzle fence, but both of them thought the fence should be made solid and that it should be made higher [8]. Discomfort glare has a discomforting effect and causes fatigue, disturbance, apprehension, and pain that reduce drivers’ ability and driving safety [9]. To illustrate the effect of glare on drivers, a method was introduced to estimate the significant effect of glare from automobile headlamps, and a previous study showed that older drivers are more sensitive to glare than young drivers [10]. The driver’s behaviors that deal with the...