Veiling glare is a type of blinding image that is created when light hits the car interior and reflects into the windshield, causing mirror-like images in the windshield, these are also known as ghost images. It is called Veiling because, like a veil, you can see through it, just not very well. "While ordinary tinted lenses reduce brightness, only polarized lenses eliminate glare. Polarization is achieved by placing a thin sheet of polarized film between two layers of material (T.a.s.c.0 et al. 2009)." It is the result of polarized lenses' special attribute that they have the ability to block blinding horizontal glare as well as veiling glare. No other lenses can achieve this result.
(See Bertilsson & Svensson P. 27 Figure 2.20)
Veiling glare is the most dangerous glare because the reflections from the dash board and other ghost like images have the ability to completely blind the drivers' point of vision. This type of glare requires polarized lenses to reduce it optimally. According to Mefford, Flannagan, and Adachi: "Light that is reflected or scattered from a vehicle windshield toward the eyes of a driver creates a veiling luminance that the driver must look through in order to see the roadway ahead (Adachi, Flannagan, & Mefford, i)." This is to say that the distribution of luminance in a given field of vision is important.
(See Bertilsson & Svensson P. 25 Figure 2.2.3)
It is because this luminance is superimposed on that scene, that it decreases all of the contrast values in the scene, including the contrasts between objects and their backgrounds, and thereby may decrease the visibility of objects and surfaces that are important for the driver to see.
(See. Bertilsson & Svensson P. 19 Figure 2.1.3)
Some countermeasures that have been considered in the past to reduce veiling glare include antireflection treatments for windshields, lower reflectance materials for the parts of the dashboard that are reflected in the windshield, and better maintenance of dirty or pitted windshields. While all of these methods make forward progress towards reducing veiling luminance there is a more simple and realistic solution towards optimally reducing the chances of veiling glare inhibiting your vision! This solution requires the use of Polarized lenses.
Of all types of glare including distracting, discomforting, disabling, and blinding glare, veiling glare can be considered as a sub-category of blinding glare and is the most dangerous because it takes the control away fiom the driver's ability to see in actuality the contrast between an object and its background. Put simply, this could mean the difference between being able to see a human being in the road, oncoming traffic, or turns in the highway, depending on the lights reflection into your windshield. Since the relative contributions of the components of veiling luminance will be different under various light conditions, depending on factors such as sun angle and cloud cover, it is always a chance that a driver takes to choose not to wear polarized lenses that would allow one to take notice of all contrasting features within that given drivers environment.
While there are other measures that can be taken to counter the chances of encountering veiling luminance, such as cleaning the windshield, inside and out; it is important to notice outside factors that increase the chances that one will encounter considering the negative effects of veiling glare.
It is in this figure that one should notice the effects of each separate 1-ce attribute. These attributes are shown on the bottom of the bar graph and read fiom left to right interior dirt, (which has twice the luminance effect if one smokes in the car) exterior dirt, dashboard reflectance, and residual scatter. The best way to ensure that these issues do not become a danger is to wear polarized lenses.
"Veiling glare has in the recent years, become more of an issue than in years past due mainly to increase in windshield rake angles and the use of brighter and glossy materials in modern cars. This has resulted in customer complaints.. . (Bertilsson et al. 42.)" These issues led to krther testing in order to find affecting factors. In this study nine factors were to be studied.. . (See Bertilsson et al. Section 4.4.1) The impracticality of testing all factors in the experiment design limited the actual findings of effect on the amount of veiling glare.
It becomes plainly evident that ". . .for daytime conditions most attention has been given to the component of veiling luminance caused by images of the top of the dashboard seen by specular reflection in the windshield (Adachi et al, i)." It is with good reason that much attention has been given in this area since research shows it has the highest effect on veiling glare. To be stated quite clearly ". ..reflection causes the majority of veiling luminance, and measures that would reduce reflected luminance potentially offer substantial benefits (Adachi et al. i.)." Sight is an iduential sense in regards to safety and precision, in order to keep you and your family safe, by eliminating veiling glare, wear high quality polarized lenses!