A few notes: In the picture, I just drew a person with a flashlight, not a car with headlights. (I believe we all agree that it is basically the same, right?) For dry roads, I randomly draw some light instead of all the different ways that light can reflect. It is important that one of these rays is returned to humans so that they can see the road.However, please note that the total amount of reflected light cannot exceed the incident light, or Towards A thing. I tried to show this by drawing lighter reflected light. In other words, the light reflected back to the observer is always darker than the amount of light originally emitted from the light source.
For wet roads, all light will be reflected Leave From the flashlight. If you are in a car coming from the other side of the road, this light will be very bright. This is why when you are driving in the rain, other vehicles on the road will make it more difficult for you to see.
Retroreflectors are used not only for lane markings, but also for traffic signs and bicycle safety devices, making them easier for drivers to see.
The retroreflector does not reflect light all The direction is like a dry road, it does not reflect light Leave From the source it looks like a flat mirror. Instead, the retroreflector directs the light back to the light source. Yes, if you irradiate the light at the mirror with 0°; the incident angle-directly facing the mirror-it will go directly back to the source. But with a retro-reflector, no matter which direction it comes from, the light will return to the source.
When you are driving, your eyes are on an airplane, and it is not far from the airplane with the headlights on. This means that the light reflects from the headlights to the lane markings and back to your eye level, and you will see that these reflectors are very bright-which is good because it helps you stay on the road.
However, if you are on the side of the road and there is a car passing by, you will not see the lane markings as bright. The light from the car’s headlights will not be reflected into your eyes from the side.
These are two pictures of the road. The top image has lines drawn, and the bottom image has lines with retroreflectors. Can you see the difference?
How to make a retro reflector
There are different designs of retroreflectors, but I will show you the two easiest ways to make it work. The first method uses three plane mirrors connected at right angles (they can be large or small according to your preference). Together these mirrors form the corner of a box. When light enters this retroreflector, it will be reflected multiple times, reflected between the mirrors, and finally returned by entering.
This is the effect of using red and green lasers. I put the two lasers at different angles so that you can see that each beam returns in the same way.