I meet both conditions, so guess i don't need to turn in the I-94. My friend who is F1 in the US side will drive me to Detriot, and i will then go to Windsor and back to Detroit in the same day finally. Sorry for confusing. My further question is which is better and efficient for me, either taking the tunnel bus or getting somebody give me a ride? Thank you so much!! -xiaomai2009(小麦) 2009-7-27