JP2000030502A - Lighting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce rear-end collisions by enhancing visibility of a preceding vehicle traveling on the road and tunnel lighting or the like, by setting a specific value for the luminance of rear surface of the preceding vehicle. SOLUTION: In a method to light the rear 3 of a preceding vehicle 2 in a tunnel 1, the rear luminance of the preceding vehicle is set for not less than 2.0 cd/m2. A luminaire to light the rear 3 of the preceding vehicle 2 is installed on the wall surface 5 or the like of the tunnel. Since the rear luminance of the preceding vehicle to enhance ability to grasp movement of the preceding vehicle 2 having any reflectance (color), on lighting excluding its own headlight in an environment such as a road and a tunnel where the preceding vehicle 2 can exist, is not less than 2.0 cd/m2, a relative speed difference from the preceding vehicle 2 is easily recognized by this method. In a road lighting, visibility of the preceding vehicle 2 from a driver is enhanced by aggressively irradiating light toward the traveling direction from the luminaire and making the rear luminance of the preceding vehicle 2 higher than 2.0 cd/m2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting system for improving the recognition (behavior) of a preceding vehicle by using a lighting device installed on a road or a tunnel.

[0002]

2. Description of the Related Art In order to prevent a black hole phenomenon occurring at the entrance of a tunnel (a phenomenon in which a sudden entrance into the tunnel from a bright environment suddenly makes the front black out and becomes invisible), the back of a preceding vehicle is illuminated at the entrance of the tunnel. There has been a lighting apparatus (Japanese Patent Application Laid-Open No. 9-259611) that cuts off light to the driver side in order to reduce a light curtain generated due to direct light from the lighting apparatus in a tunnel basic part.

[0003] However, there has been no illumination system for positively illuminating the rear surface of the preceding vehicle in order to improve the appearance (behavior of behavior) of the preceding vehicle.

[0004]

According to reports investigating the causes of traffic accidents on expressways, rear-end collisions with the preceding vehicle are the most frequent. Despite this situation, no lighting system has been devised to improve the appearance of the preceding vehicle in order to reduce rear-end collisions. Another reason for misinterpreting the appearance of the preceding vehicle is the presence of tail lamps. The brightness of the tail lamp makes the presence of the preceding vehicle itself clear, but in the situation where only the tail lamp can be seen, the distance and speed between the left and right of the tail lamp differ depending on the vehicle type, so the distance and speed difference from the own vehicle are mistaken. It becomes a factor.

[0005] In a rear-end collision, the driver cannot recognize the relative speed difference with the own vehicle, such as whether the preceding vehicle is running at the same speed as the own vehicle, decelerating, or stopping. Get up if. From this, improving the appearance of the preceding vehicle to reduce rear-end collisions means making it easier to recognize the relative speed difference from the preceding vehicle.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an illumination system which reduces a rear-end collision with a preceding vehicle and improves the appearance of the preceding vehicle during traveling by lighting a road or a tunnel.

[0007]

According to the first aspect of the present invention, there is provided an illumination system for illuminating a rear surface of a preceding vehicle in an environment where the preceding vehicle may exist, wherein the luminance of the rear surface of the preceding vehicle is 2.0 cd / m ^2.
That is all. According to the lighting system of the first aspect, it is possible to improve the appearance of the preceding vehicle during traveling by road and tunnel lighting, etc., to make it easier to recognize the relative speed of the preceding vehicle, and to reduce a rear-end collision with the preceding vehicle. is there.

According to a second aspect of the present invention, in the first aspect, the environment in which the preceding vehicle can exist is in a tunnel. According to the illumination system of the second aspect, the same effect as that of the first aspect is obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. That is, this illumination system is an illumination system for illuminating the back surface 3 of the preceding vehicle 2 in the tunnel 1, and has a front vehicle back surface luminance of 2.0 cd / m ² or more. 4 is a road surface, 5 is a wall surface, and 6 is a top surface, and the wall surface luminance is set to 1.5 times the road surface luminance. In FIG. 1, the height is 1524 mm and the width is 6130 mm. A lighting device for illuminating the rear surface of the preceding vehicle 2 is installed on the wall surface 5 or the like, but details are omitted.

A dynamic visual environment evaluation experiment using computer graphics was performed to clarify the relationship between the recognition of the relative speed difference between the own vehicle and the preceding vehicle 2 and the back luminance of the preceding vehicle 2. The outline of the experiment is as follows. The experiment was performed by presenting a moving image as shown in FIG. 1 to the subject. The average road surface brightness in FIG. 1 is from 2.5 cd / m ² to 16.0 cd / m ^2.
And the back luminance of the preceding vehicle 2 is approximately 60 cm in diameter at the center of the rear surface 3 of the preceding vehicle 2 in FIG.
Average luminance in the circle 7 from 0.5 cd / m ² to 7.0 cd
/ M ² . The center of the circle 7 is located at the lowest point of the window in the vertical direction and at the center of the preceding vehicle 2 in the horizontal direction. The portion of the rear surface 3 is approximately 0.1 cd / m ² of the window and the tail lamp having a substantially constant luminance, the luminance of the tire is substantially constant, and the portion is a portion where the luminance is changed. Brightness. The running speed of the vehicle is always 1 per hour
00 km, and the speed of the preceding vehicle 2 was changed between 35 km / h and 60 km / h. At this time, the subject sees the preceding vehicle 2 as if approaching.

Next, the experimental paradigm will be described. First, subjects performed dark adaptation for 5 minutes, adjusted their eyes to darkness,
The set of moving images is observed for 5 seconds each. The first group is a moving image in which the relative speed difference with the preceding vehicle 2 is always constant, and is defined as a reference moving image. The second set of moving images changes the relative speed difference with the preceding vehicle 2 at each experimental trial, observes these two sets of moving images, and forcibly selects which moving image has the higher relative speed. Responded with a choice. And this correct answer rate is 50
% Is determined as a threshold value for recognizing the relative speed difference of the preceding vehicle 2, and this threshold value is determined for each preceding vehicle rear surface luminance. The results are shown in FIGS. That is, in these graphs, the horizontal axis represents the sensitivity to the rear vehicle front luminance (1 / speed difference threshold), (a) is the average road luminance of 16 cd / m ² , (b) is the average road luminance of 10 cd / m ² in the case of,
(C) in the case of the average road surface brightness 5cd / m ^2, (d) shows the case of the average road surface brightness 2.5 cd / m ^2. Subject is 2
There were five visually clean men who were accustomed to the visual environment evaluation experiment from the 0s to the 40s.

From the results of FIGS. 3A to 3D, the general tendency is that the higher the rear surface brightness of the preceding vehicle 2 is,
It was found that the relative speed difference was easy to recognize. That is, it can be said that it is better to make the rear surface brightness of the preceding vehicle 2 as high as possible to prevent a rear-end collision. Looking at the experimental results in a little more detail, if the average luminance of the road surface 4 of the tunnel 1 is 10 cd / m ² or more, the rear luminance of the preceding person becomes 2.
A decrease in sensitivity is observed around 0 cd / m ² , and 2.0 cd / m ²
A slight increase in sensitivity was observed below m ² . This is considered to be due to the fact that the rear luminance of the preceding vehicle 2 is extremely low with respect to the road luminance, so that the luminance contrast between the two is extremely high. However, considering the actual tunnel 1, when the average road surface luminance is 10 cd / m ² or more, the rear surface luminance of the preceding vehicle 2 cannot be 2.0 cd / m ² or less. The sensitivity increase below 0.0 cd / m ² is ignored.

When the rear brightness of the preceding vehicle 2 in the current general tunnel 1 is examined, the value is about 2.0 cd / m ² , and the relative speed of the preceding vehicle 2 is the highest in the experimental results. The difference is the back luminance that the difference is hard to recognize,
Rear-end collisions are most likely to occur. Therefore, in the future highway tunnel 1 in which the speed limit is further increased, the rear luminance of the preceding vehicle 2 is set to 2.0c.
d / m ² must be as high as possible.

As a result, as a result of a subject experiment using the relative speed difference recognition rate by changing the rear luminance of the preceding vehicle 2 (the brightness of the preceding vehicle seen by the driver), the luminance was 2.0 cd / m2.
It was found that the recognition rate increased when the score was ² or more. Therefore, by adopting an illumination system that satisfies this condition, it is possible to illuminate the rear surface of the preceding vehicle 2 and obtain a rear luminance of 2.0 cd / m ² or more even for a vehicle having a low reflectance while securing the conventional average road surface luminance. Can be achieved.

According to this illumination system, the target is illumination other than the headlights of the own vehicle in an environment where the preceding vehicle 2 can exist, such as a road or a tunnel, and the behavior of the preceding vehicle having any reflectance (color) can be grasped. The relative brightness difference between the preceding vehicle 2 and the preceding vehicle 2 can be easily recognized by improving the preceding vehicle rear surface luminance (the luminance in a circle having a diameter of 60 cm in FIG. 2) of 2.0 cd / m ² or more.

For this reason, for example, light is actively irradiated in the traveling direction from the lighting equipment in the tunnel basic part, and the back luminance of the preceding car (black painted car in consideration of the safety side) 2 is 2.0 cd / m2. ^By setting the value to a value higher than 2, the visibility of the preceding vehicle 2 from the driver can be improved, and the risk of collision with the preceding vehicle 2 can be reduced. Also, in road lighting (pole lighting, row lighting, catenary lighting, sound insulation wall lighting, etc.), light is actively radiated from the lighting fixture in the traveling direction, and the back luminance of the preceding vehicle ² is higher than 2.0 cd / m ^2. The value can improve the visibility of the preceding vehicle 2 from the driver, and reduce the risk of a collision with the preceding vehicle 2.

Furthermore, the reflection luminance of a highly reflective object (such as a lane mark having a reflective reflectivity or an obstacle having a high reflectance) existing on a road or a tunnel road surface is increased, and the visibility of the object is improved. . Note that the lower limit of the backside luminance is 2.0
The upper limit is cd / m ² or more, but the upper limit is determined in consideration of the power consumption and glare of the lighting equipment.

[0018]

According to the lighting system of the first aspect, the visibility of the preceding vehicle during traveling is improved by road and tunnel lighting and the like, the relative speed of the preceding vehicle can be easily recognized, and the vehicle collide with the preceding vehicle. Accidents can be reduced. According to the illumination system of the second aspect, the same effect as that of the first aspect is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a tunnel to which an embodiment of the present invention is applied.

FIG. 2 is an enlarged rear view of the preceding vehicle in FIG. 1;

FIGS. 3A and 3B show the sensitivity to the luminance of the front vehicle rear surface, and FIGS.
(D) is a graph in each case where average road surface brightness differs.

[Explanation of symbols]

 1 tunnel 2 preceding vehicle 3 back 4 road surface 5 wall

Claims (2)

[Claims] An illumination system for illuminating the rear of a preceding vehicle in an environment where the preceding vehicle may exist, wherein the luminance of the rear of the preceding vehicle is 2.0.
An illumination method characterized by being at least cd / m ² . 2. The lighting system according to claim 1, wherein the environment in which the preceding vehicle can exist is in a tunnel.