A couple of comments: In the diagram, I just drew a man with a flashlight instead of a car with headlights. (I’m sure we can all agree that it’s basically the same thing, right?) For a dry road I drew a few random rays of light, but not all the different ways in which light can bounce. The important thing is that one of these rays goes back to the person so that they can see the road. Note, however, that the total amount of reflected light cannot be greater than the incident light or the light that goes yes object. I tried to show this by drawing reflected rays of a lighter color. In other words, the light reflected back to the viewer is always dimmer than the amount of light originally emitted from the source.
On a wet road all the light is reflected away from the flashlight. If you were sitting in a car that was approaching from the other side of the road, that light would be bright. That’s why other cars on the road can doubly interfere with seeing when you’re driving in the rain.
Reflectors are used not only to mark lanes, but also for road signs and bicycle safety devices to make them more visible to drivers.
The reflector does not reflect light everything directions like a dry road and it does not reflect light away from the source like a flat mirror. Instead, the reflector directs the light back to the source. Yes, if you shine a light in a mirror with 0 & deg; the angle of incidence – directly to the mirror – it will return directly to the source. But with a reflector the light will return to the source, no matter which way it goes.
While driving you are looking at a plane that is not so far above the headlight. This means that the light is reflected from the headlight to the lane marker and returns to the level of your eyes, and you see these reflectors bright – and that’s good because it helps you stay on the road.
But if you are on the side of the road and a car is passing by, you will not see bright lane signs. No headlights of the car will be reflected from the side and into the eyes.
Here are two images of roads. The top picture shows the lines, and the bottom – the reflectors. Can you notice the difference?
How to make a reflector
There are different designs for reflectors, but I’m going to show you two simple ways to make them work. This first method uses three flat mirrors (they can be as large and small as you like) connected at right angles. Together, these mirrors make up the corner of the box. When a light beam hits this reflector, it produces multiple reflections, bouncing among the mirrors and eventually returning the way it entered.
This is what it looks like with red and green lasers. I put two lasers at different angles so you can see that each beam of light returns in the same way it entered.