An unseen, low-flying object was emitting a beam of light on the ground coming towards us.

I was 12 years old and my friend and I were hanging out in the street in front of our house around 6:30 or 7:00 p.m. in the summertime.  
All of the sudden, we could hear a low humming sound coming up the street.  It was lower than the power lines and trees.  Then we saw a beam of light coming up the street very slowly towards us.  We watched as it got closer.  All you could see was the light on the ground, no visible shape or object and no where to see where the beam of light was coming from.
As the light got within a few feet of us I told my friend to run and we ran into our own houses.  I told my family at the time, but they didn’t believe me because sometimes I would make up stories to get a reaction out of them.  So no one ever believed us.  
After I had time to think about it, I realized I had initially thought it was a helicopter overhead.  But it was too quiet and too low.  
I wondered about it my whole life.  I wondered what would have happened if we had let the beam actually reach us and shine on us.  
Too bad I was young and scared and ran away.
Witness indicates that the date of the incident is approximate.  PD