Firstly, it's important to understand that the brightness of the headlight is not the only factor that affects glare. The glare from a headlight is actually caused by the angle at which the light is directed. When we use high beams, the light is directed at a higher angle, which can cause the light to directly shine into the eyes of the oncoming driver, creating a temporary loss of vision and discomfort.
On the other hand, low beams are angled downwards, which ensures that the light is directed towards the road and not directly into the eyes of the oncoming driver. In addition, the shape of the low beam light pattern helps to reduce glare by preventing the light from scattering in all directions. Instead, the beam is focused and directed towards the road ahead.
To better understand this, let's take an example of a flashlight. Imagine you're in a dark room and you point a flashlight straight ahead. The beam will shine straight into your eyes and cause discomfort. However, if you angle the flashlight downwards towards the ground, you will still be able to see where you're going, but the light won't directly shine into your eyes. This is essentially how low beam headlights work.
In summary, the angle at which the light is directed is the primary factor that determines whether a headlight will cause glare or not. While high beams are brighter than low beams, they are also directed at a higher angle, which can cause discomfort and temporary loss of vision to oncoming drivers. On the other hand, low beams are angled downwards and have a more focused beam pattern, which reduces the glare and ensures that the light is directed towards the road ahead.
It's important to always use the correct headlights in different driving conditions and avoid using high beams when there is oncoming traffic. Not only is it safer for everyone on the road, but it also ensures that you're not causing discomfort to other drivers.