What if car moving in speed of light, turns its headlights on?
As an object approaches the speed of light, its mass rises precipitously. If an object tries to travel 186,000 miles per second, its mass becomes infinite, and so does the energy required to move it. For this reason, no normal object can travel as fast or faster than the speed of light.
However, if you are powerful enough, energy equal to the product of the mass of the car and the speed of light will be produced. E = mc^2
Or more hypothetically, the driver may not see anything ahead if it is a night drive.
Correct me if I am wrong.
From what I know, nothing having mass can travel at the speed of light, and conversely, if something has no mass it must travel at the speed of light, so a car with mass can never travel at the speed of light.
And spacetime compresses so much at the speed of light that all the points on the space coincide with each other such that you can reach any part of the universe in 0 time (time completely stops from the point of view of the body traveling at the speed of light).
However, if the car was traveling at a speed close to that of light then the spacetime will compress and the time will slow down from the point of view of the driver such that the light of the headlight travel at the speed of light both for the driver as well as the person viewing it from outside the moving car.
And also as the driver is traveling very fast, due to the doppler effect, he will see the world in front of him to be blue-shifted, as in such speeds the change in the wavelength of the light is noticeable and the world behind him would look red-shifted as the wavelength of light decreases from the driver's point of view.
For a more detailed explanation with visualization refer to these videos: