Looking at the ground beside a moving vehicle helps you judge its
Looking at the ground beside a moving vehicle ensures you see if they are coming into your lane or not.
show that you are moving, and in what direction
proximity
Yes. when you look at the tires of a vehicle (we call "ground viewing") you can tell the speed and if the vehicle is moving toward you.
blind spots
proximity
I can also say that if you look out of the car window and see what you are passing by for example, different trees, buildings or other objects if they are near you then you will indeed be able to tell the vehicle in a moving state and at the speed.Example: the car is running at 100 km/h which is quite fast. If you look up in the sky at the clouds then you will think it is moving slowly because the sky is so far away. But if you pay attention to the objects that on the ground proximal to the road like the buildings, street lamps then you can tell it is moving fast since all of those objects are near to you.
You fall when you jump from a moving vehicle because you get the moving vehicle speed and immediately you have your feet on a stable ground and you have either to stop all of sudden or to run at the vehicle speed (that is higher than your capacity) .
When looking out the window, if you focus on a distant building outside the train, it may appear that the train is not moving because the building is not changing position relative to the train. However, if you look at a nearby platform or another train beside yours, you may notice the train's movement compared to these closer reference points, making it appear that the train is indeed moving.
From the perspective of an observer inside the vehicle, everything inside it appears to be stationary or moving at the same speed as the vehicle (30 miles per hour) due to inertia. This means that if you were inside the vehicle and not looking outside, you would not feel the motion.
I'm having the same problem. It only happens when vehicle is moving, so I suspect a bad ground.