I have never seen or head of another experience like this

I was driving home in the early hours of the morning through a resdential are, all of a sudden I noticed a small triangular "object" just 10cm above the front right headlight. As I drove along it stayed the same distance away from the front of the car - it appeared as an "upsidedown" triangle and looked like it was made from black perspex it was 20cm top to bottom and 15 mm depth, no lights, no noise, nothing, after approx 10 sec it slowly moved straight down and dissapeared in front of the car out of site, thats was it, there was nothing on the fornt of the car when I got out, I dont know why I didnt stop the car, I didnt feel frightened just remember thinking curiously "what the **** is that." I have never posted this story (or any other story) I have only mentioned it to a couple of close friends so Im not really sure why I am posting this now
Date is unknown.  We have requested that the witness attempt to establish the date of the incident, to the best of his ability.  PD