I am from Sioux Falls which has the north/ south and the East/West interstates running through them or very close. It is amazing the number of bikes on the interstate for several weeks prior and a week after.
Was there this year. Didn't spend much time in Sturgis. Can only look at the same 50 tshirts in one of the 300 tents so many times. Lots of people watching on the strip though. Roads were packed and the weather was awesome though. Can't wait until next year!