Why is lane one vacant on a running track?

It is all due to the corners(all lanes are used in straight sprint i.e under 100m). The corners on the track are much more narrow as you get closer to the middle. It has been determined that your time is effected(slower) on the inside lane than any other lane. The angles of the corners in lane 2-8 have not shown a drop in time and are therefore able to be used fairly.