Sun Glare: Network Characterization and Safety Effects

Abstract

This research conducted a two-stage assessment to investigate sun glare effects on road safety in Edmonton. The first stage developed a methodology to model sun glare occurrence, aiming to identify when and where drivers are most likely to be exposed to sun glare. Safety risks at those identified locations during sun glare periods were assessed in the second stage. By contrasting the collisions during glare and non-glare conditions, this second stage aimed to quantify the effects of sun glare on road collisions. Consequently, three major findings were concluded. First, sun glare was found to significantly contribute to collision occurrence, especially at road intersections. Second, the effects of sun glare on collision occurrence during mornings on the eastbound and evenings on the westbound were observed to be particularly worse in the spring and fall months. In fact, safety in the southbound direction was significantly affected by sun glare during most daytime hours in the main winter months (November, December, and January). Lastly, the analysis revealed that certain collision types were more likely to occur during periods of sun glare. For example, collisions due to signal violations and failing to yield to pedestrians/cyclist were more likely to occur at intersections. At mid-block locations, the proportion of collisions occurring due to improper turning and lane changes were observed to be significantly higher. Overall, the approach proposed in this research provides a holistic method to quantify the effects of sun glare on road collisions and offers additional insights into the extent by which sun glare affects road safety.

Population-based case–control study of the effect of sun glare on pedestrian fatalities in Taiwan

“…Adding to the research conducted by Sun et al ,14 who reported that crashes related to improper turning or lane changing were more likely to occur during periods of sun glare, the present study reveals an association between the execution of overtaking manoeuvres during periods of sun glare and pedestrian fatalities. Injuries sustained in crashes caused by vehicles executing overtaking manoeuvres are commonly severe because motorists must accelerate to overtake other vehicles.…”

“…By analysing the traffic-crash database of Chiba, Japan, Hagita and Mori13 revealed that crashes involving pedestrians or bicycles at intersections were more likely when the sun was below 45° above the horizon in the driving direction. Sun et al ,14 analysing police-reported crash data in Edmonton, Alberta, Canada, reported similar findings, concluding that sun glare significantly contributed to crash occurrence, especially at intersections. Furthermore, they indicated that the effect of sun glare on crash occurrence during mornings on eastbound roads and evenings on westbound roads is significantly greater during the spring and autumn months and that certain crash types (eg, crashes related to signal violation, failure to yield to pedestrians/cyclists and improper turning and lane changing) are more likely during periods of sun glare.…”

“…It is therefore not surprising that more crashes occur on roadways that experience a significant portion of traffic during peak morning (sunrise) and afternoon (sunset) hours. The adverse effect of sun glare on crash occurrence has been well-documented in relevant literature 3 14. However, Mitra3 discovered that motorist injury severity was not increased in glare conditions, possibly as a consequence of reduced travel speed 8.…”

Measuring the Behavioral Effects of Intraocular Scatter

“…This scatter distorts the image's representation on the retina and produces a disrupted depiction of the visual scene. Most major accidents related to glare happen due to daytime intraocular scatter caused by the sun 1 . This origin means that time of day and season (solar position) are significant variables as well as the age of the driver 2 , 3 .…”

Solar Blue Light Radiation Enhancement during Mid to Low Solar Elevation Periods under Cloud Affected Skies

“…Cloud variability and high SZA (above 70°) has been observed to cause an increase in uncertainty in solar irradiance observations, which includes HEV [ 13 , 33 ]. Some clouds, particularly thin clouds, can appear very bright when they are close to the vicinity of the sun [ 34 , 35 , 36 ], resulting in the forward scattering of sunlight through the optically thin clouds [ 34 ].…”