I driving on my way back from the hospital and went onto a highway towards home. it was about a fifteen minute drive but felt much longer that night. no vehicles in sight. out of nowhere a bright yellow coloured light appeared in my rear view mirror nearly blinding me. i thought it was a vehicle behind me at first. i continued driving and slowed down a little, hoping it was pass me. that's when it started to speed up and that's when i realized it was above the car, maybe a 20 foot distance. i noticed it was a bright yellow orange colour and glowed. i could not make out the details as it was too bright. i sped up to get away from it but it continued at the same speed overhead. for fifteen minutes it remained this way. when i got closer to my destination, i went down a hill to get to my turn and slowed right down. the ufo then abruptely changed direction towards where i was headed to. hovered above the property then the ufo glowing light went dim and disappeared into the darkness of the night.