I remember watching this movie when I was little but I can't remember what its called. The semi-trucks in the movie drive by themselves and I remember seeing a green glowing light in the sky. Ring any bells to anyone? This is driving me nuts!

Sounds like this one could be the 1986 opus Maximum Overdrive, directed and written by Stephen King and starring Emilio Estevez, old-timer Pat Hingle, and Yeardley Smith of The Simpsons fame.