The Effect of Sun Glare: Concept, Characteristics, Classification

Abstract

Investigations have been carried out to determine the types of the driver's sun glare in order to fully take into account all the factors affecting the handling of the vehicle under the effect of sun glare (ESG). The results of studies on the change in the average speed of the vehicles in the “sun glare danger” areas and the results of drivers’ testing have been provided. The description of specialized programs to determine the “sun glare danger” areas on the road is given. The characteristics of ESG are provided: its area and force of impact, period and duration. The classification of the ESG by its duration and the location of the sun is suggested.

Full text

Transportation Research Procedia 20 ( 2017 ) 474 – 479
2352-1465 © 2017 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of the organizing committee of the 12th International Conference “Organization and Traffic Safety
Management in large cities”
doi: 10.1016/j.trpro.2017.01.077
Available online at www.sciencedirect.com
ScienceDirect
12th International Conference "Organization and Traffic Safety Management in large cities",
SPbOTSIC-2016, 28-30 September 2016, St. Petersburg, Russia
The Effect of Sun Glare: Concept, Characteristics, Classification
Pavel Pegin 1a
*
, Elena Sitnichuk 2b
1 Saint Petersburg State University of Architecture and Civil Engineering, 4 2nd Krasnoarmeyskaya str., Saint Petersburg, 190005, Russia
2 Pacific National University, 136, Tikhookeanskaya ul., Khabarovsk, 680035, Russia
Abstract
Investigations have been carried out to determine the types of the driver's sun glare in order to fully take into account all the factors
affecting the handling of the vehicle under the effect of sun glare (ESG). The results of studies on the change in the average speed
of the vehicles in the "sun glare danger" areas and the results of drivers' testing have been provided. The description of specialized
programs to determine the "sun glare danger" areas on the road is given. The characteristics of ESG are provided: its area and force
of impact, period and duration. The classification of the ESG by its duration and the location of the sun is suggested.
© 2016 The Authors. Published by Elsevier B.V.
Peer-review under responsibility of the organizing committee of the 12th International Conference "Organization and Traffic
Safety Management in large cities".
Keywords: effect of sun glare, traffic safety, traffic accident, motorway, sun glare danger area, classification of sun glare, types of sun glare
danger areas.
1. Introduction
Concept of sun glare effect. The sun glare adversely affects the perception of road conditions leading to faster
fatigue and reduction of driver's performance. Sun glare leads to distortion of the road conditions, and in some cases
the driver is so blinded by the sunlight that he or she does not perceive the objects located ahead. As a result, the driver
does not have time to adequately take into account all the factors on the road, which leads to road traffic accidents
(RTA). The experimental evaluation of the influence of the effect of sun glare (ESG) on the drivers showed significant
changes in their psycho-physiological qualities and as a result – a reduction in vehicle speed.
* Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 .
E-mail address: ppavel.khv@gmail.com a*, 003757@pnu.edu.ru b
© 2017 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of the organizing committee of the 12th International Conference “Organization and Traffic Safety
Management in large cities”

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Pavel Pegin and Elena Sitnichuk / Transportation Research Procedia 20 ( 2017 ) 474 – 479
During the days of intense manifestation of the ESG on the roads the running speed is significantly reduced, and
road transport companies are suffering losses. Because of this factor, the annual value of lost time in some regions of
Russia comes to 268 hours, or about 33 job orders. According to preliminary calculations, the annual loss of the
national economy from the negative effects of the ESG is around 25 billion rubles [Pegin (2010)].
The analysis of accidents on the motorways in the Far East region showed that more than 25 people are killed or
injured in the sun glare danger areas annually. By the severity level, the accidents are classified as very dangerous.
On average one accident accounts for 3.9% of participants; 59.4% are wounded and 2.8% are killed [Pegin (2015)].
The sun glare during daytime (Fig. 1) has been little studied as a natural phenomenon that adversely affects the
safety.
The sun glare has a dual impact: physiological and psychological. The physiological impact reduces the sensation
of contrasts, sharpness and speed of perception. The psychological impact of the ESG is manifested in the increased
nervousness, anxiety and stress, reducing the switching of attention, changing the focus [Vasilyev (1976), Romanov
and Pegin (2006)].
The sun glare primarily affects the visual perception of the driver: visibility distance and sight are reduced,
temporary blindness occurs, etc [Pegin (2002)].
Fig. 1. Effect of Sun Glare.
The short-term feeling of discomfort in the process of adaptation of the eyes to bright light is normal (light
adaptation), although on a very bright sunny day the adaptation may take up to 5 minutes.
2. Main part
The effect of solar glare is a psycho physiological process reducing over a period of time required for the transition
to a new level of adaptation due to the abrupt change in the brightness level of the road conditions experienced by the
driver. It happens due to the impaired visual perception and the deterioration of the emotional state of the driver.
Even total blindness, which can sometimes occur after a look at the sun, is nothing more than a false visual
perception. A vehicle driver feels pain from the unexpected and bright sunlight, the cause of which in such cases is
not the brightness of the light, but something like a shock that a person experiences in case of a sudden change in light
intensity. In this situation, you need to soothe and relax the eyes to the light.
Vehicle

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Characteristics of the effect of sun glare
The main characteristics of the sun glare effect are: sector (area) and the force of impact, period and duration of
the ESG.
Sector of ESG impact is a part (area) of the horizon, located above the motorway, at the intersection of which by
the light path the effect of sun glare is shown [Ponomaryov (1991), Brinkworth (1976), Pandul (1983), Romanov and
Pegin (2006)].
Force of impact of ESG is a measure of the impact of sunlight on the physiological quality of the driver while
driving. The essence of this impact is the ability to create a sense of brightness when exposed to the human eye. Inside
the area of the ESG influence the subzones are conventionally arranged, which differ in the degree of exposure to the
ESG. The impact of the ESG on the visual organs will decrease with respect to the radial distance from the point of
maximum impact.
Period of ESG is the number of days, during which the effect of sun glare will be present in a certain section of
the road. The ESG period is 11 days for the adopted theoretical framework since particularly during this period the
daily paths of the sun will pass the impact area of the ESG.
There are two kinds of ESG periods for a section of a road with a known azimuth:
x The first type is a section of road with one period during the year;
x The second type is a section of road with two periods during the year.
ESG duration is a daily duration of the sun stay in the ESG sector, which is measured in minutes. In accordance
with the adopted scheme this time corresponds to the time of sun passing the sun glare danger area that corresponds
to the horizontal angle of 14° and angle of declination of 18° [Pegin (2015)]. This corresponds to a horizontal daily
drift of the sun. The ESG duration in a particular straight section of the road is 28 days. The maximum effect of sun
glare occurs when the sun is situated at the axis of the roadway. During this period, the direct visibility distance is 5-
10 meters, and the driver is not able to perceive the traffic situation and respond to changes in it.
Classification of the effect of sun glare
In order to systematize the manifold kinds of effect of sun glare, we propose the following classification of the
ESG:
x by the time of impact;
x by the extent of the negative impact;
x by the location to the horizontal plane;
x by the location to the motorway plane;
x by the kind of impact;
x by type.
By the time of the impact on the driver, sun glare can be divided into three categories: short-term (up to 16 min),
average term (16-32 min), long-term (32-48 min) [Pegin (2002)]. The time of impact depends on the length of the
straight section of the road, longitudinal slope and direction of movement.
Depending on the location of the sun in relation to the horizontal plane and the road axis, the ESG can be classified
into the following types:
1. in the horizontal plane (sunrise and sunset)
2. at an acute angle to the horizontal plane (up to 45º),
3. at an obtuse angle to the horizontal plane (more than 45º).
In the classification of the ESG we need to clearly distinguish the position of the sun relative to the horizontal plane
and to the road surface. The sun can be located both in the road plane and in a plane at an angle to the road plane. The
sun may be positioned anywhere in the hemisphere above the road plane.
By the kind of impact, the ESG can be classified into direct and indirect impact. A direct impact is an ESG, where
the sun shines directly into the driver's face (frontal). Indirect impact of ESG can fall into several subtypes, reflected
from mirrors; from the hood; from side window; from the wet surface of the road; from the snow surface.
The indirect sun glare has a lesser brightness but it is as dangerous as a direct one, especially in case of long-term
exposure. Prolonged exposure to the indirect ESG is often manifested on the winter roads. Depending on the duration
and frequency of manifestation of ESG, sections of roads can be divided into five types (Table 1).

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Table 1. Scale of sun glare danger of segments of motorway (by P.A. Pegin)
Type of effect of sun glare
Segment characteristics
0
Without the effect of sun glare
I
With short-term manifestation of ESG once per year
II
With short-term manifestation of ESG 2 times a year
III
With long-term manifestation of ESG once per year
IV
With long-term manifestation of ESG 2 times a year
In order to determine the sun glare danger areas, we have developed a special program that allows identifying
hazardous areas both on the existing roads, and on the roads being designed (Fig. 2). The algorithm of the program
consists of three phases: I – determining azimuths of the surveyed roads; II – determining the azimuth of sunrise and
sunset for a given area; III – determining the date and time of the ESG manifestation.
In addition to the azimuth of the road, the period of the ESG manifestation is affected by the longitudinal slope,
latitude and longitude of the track. The insertion of variable data values is taken into account by the program to adjust
the date and time of the ESG manifestation on the surveyed segment of the motorway. The values of all azimuthally
located coordinates are specified in degrees and minutes in the designated text boxes below each graph.

478 Pavel Pegin and Elena Sitnichuk / Transportation Research Procedia 20 ( 2017 ) 474 – 479
Fig. 2. “ESO-09” Program Control Elements.
1 – Sunset and Sunrise Time Estimates, 2 – Consider Day-Light Saving Time, 3 – Longitude, 4 – Straight Rhumb, 5 – NW (North-West), 6 – N
(North), 7 – NE (North-East), 8 – Forward Sun Glare Effect Will be on May 26st 2016 From 07:05 to 07:25, 9 – Longitudinal Gradient, 10 –
Permille, 11 – Sun Glare Effect in the Reversed Direction Will be on September 01st 2016 From 21:19 to 21:39, 12 – E (East), 13 – SE (South-
East), 14 – S (South), 15 – SW (South-West), 16 – W (West), 17 – Minute, 18 – Grade, 19 – Back Bearing, 20 – Back Azimuth, 21 – Forward
Azimuth, 22 – Latitude, 23 – Time Zone, 24 – Year
Analysis of the azimuth of the tracks and sunrise and sunset shows at what time and day what sections of the
motorway will be subject to the effect of sun glare during the year.
23
22
11
21
16
15
14
13
12
17
18
19
20
24
1
2
3
4
5
6
7
8
9
10

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3. Conclusion
Determination of types and kinds of the sun glare danger segments will allow choosing the optimal variant of
measures to prevent and protect the driver from the ESG to ensure smooth and fast movement. Further study of the
effect of sun glare will improve the consumer properties of motorways and effectively apply the sun-protective
measures to ensure traffic safety.
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