If I came up alongside them without looking at them they would not snap their head to look at me. Most of the time drivers do not look at the driver in the car next to them. However, if I came up alongside them while looking at them, most of the time they seemed to be able to sense they were being looked at and turn to look at me.

This article describes one situation of sensing when someone stares at you:

https://bigthink.com/surprising-science/why-is-it-you-can-se...

However, in the situation I describe, they are looking at the road ahead and not noticing me or where I might be looking. They seemed to be able to sense that I was looking at them before they even noticed that I was there.

"However, in the situation I describe, they are looking at the road ahead and not noticing me or where I might be looking. "

There is something called peripheral vision

https://en.m.wikipedia.org/wiki/Peripheral_vision

If there is a movement in the corner of the eyes, like someone turning their head towards you, you can spot it subconsciously, or if you trained it a bit, consciously.

Yes, I'm aware of that. That's why I experimented with being further behind out of their peripheral vision

My gut tells me 1.) We are very good at recognising if something/someone is looking at us, 2.) Our peripheral vision is wider than we realise and information from it somehow goes straight to the unconscious mind.

That being said I don't think some sort of telepathic phenomenon happening here would be the strangest thing in this universe

> If I came up alongside them without looking at them they would not snap their head to look at me.

How did you know they were not looking at you if you were not looking at them? I suspect the answer to the mystery lies here.

I could see them in my peripheral vision. As long as I did not stare at them they did seem to mind

Yes. Peripheral vision! That's it!

Ok. Solved. They used their peripheral vision. When you looked at them they saw it, and would look at you