This happened to me a few months ago when a friend was staying down in the area. We both live in a rural part of the UK, but his home was really out in the middle of nowhere and can only be accessed via a small, winding, desolate road with no lights.
I had recently passed my driving test and so naturally I offered to drive us both over to the neighbouring town to spend the evening together. He gave me directions to get to his place and I set off. After initially missing the turning I eventually got on the right road, and after numerous checking of the map he gave me, finally managed to find his place. It was pretty dark when I went to get him, but not pitch black.
After the evening, I drove him back to his place. He got out and I drove back along the road alone. This time however it felt a lot different to when I first went along the road alone earlier in the evening. All along the dark road I constantly felt like somebody was behind me, following and watching. I looked over my shoulder twice but couldn't see anything.
When I looked over my shoulder the second time, I looked backwards and standing on the right hand side of the road was the figure of a girl who looked to be about 5 1/2 feet tall. In the second I had before I passed, I got a quick glance at her and the two features I remember most vividly was her long, black straggly hair and her face - which had no features. As I drove past her I could sense that she was staring at me as her head was turning to follow me as I drove by. The other thing that struck me as unusual was that she was completely colourless. She was an extremely pale shade of grey with shades of blue.
As soon as I passed her I stopped the car and looked around but she had vanished. Figuring that getting out of the car and looking for her wouldn't be a very good idea, I drove off back home, very shaken.