Furiously-Fast and bmwe30m3 are still obivously "driving very fast on a small chunk of asphalt around cones in different figures". The other two... not so obvious.
I think such a long voting is pretty good. Maybe a whole week is a bit too much but that way, more people can vote and by some time you can clearly see two or three competitors that have a high chance to win so these potential winners can choose a theme in their mind before the poll ends.