Lights in the night sky tracked us after completing maintenance on an ICBM

It was the winter of 1976-1977, I was traveling south on Interstate I15 at approximately 0200 hours, in rural Montana, north of the town of Dutton.  I was a member of Minuteman Maintenance team, returning to our base at Great Falls, Montana, after completing diagnostic systems work and returning a missile to launch ready state.
My team chief, an Air Force officer, and our security guard, were asleep, while I drove after a long dispatch.  I became aware of three points of red lights, in a triangular shape, that was visible just below the roof line of the truck windshield.  I had no idea what it was, and continued to keep an eye on it.  Its relative position never changed over a period of approximately ten minutes or more.
My team chief woke up, and asked what I was looking at.  I directed his gaze to the lights, and told them I had been observing them for some time, and that they seemed to be keeping pace with us.  We continued to watch for another five minutes, while theorizing what they were.
My officer, formerly an Air Force pilot, pointed out the light configuration was not anything he encountered in aviation.  We continued this discussion as we watched, and suddenly the lights made a 90 degree turn and left in a slight blur of red light.  It was incredibly fast.
My officer and I then discussed whether or not to report it.  He was aware of pilots who made reports of unidentified objects being subject to ridicule, harassment and obstacles to career advancement.  We were both subject to the Human Reliability Program, and could have our security clearances pulled as a result.
We decided to keep it to ourselves.