I'm a Terrible Eyewitness

I was driving east on I-84 yesterday through western New York, on a snow covered road, when right in front of my car two other cars collided at 60 mph sending each other spinning with one colliding into a guard rail on the right side of the road in front of me; the other colliding with a cable guardrail in the median behind me.  I managed to narrowly avoid being involved in the accident myself and pulled over.  I got out of my car to check on the driver of the car behind me (she appeared to be okay), while my girlfriend called 911. When I turned around to check on the other car, it was gone.