For reference for all who wish to apply for TRV at Detroit consulate:
In-person Service
Detroit allows in-person same day service for TRV for some nationals. If you want to submit in person, your application must be submitted before 11:00 am to be eligible for potential same-day service. Any visa application received after 11:00 a.m. will be processed as a mail-in application. Their in-person visa hours are Monday, Tuesday, Thursday, and Friday, 8:30 a.m. – 11:00 a.m. (For example, Indian students could extend TRV on same day)
Mailing Service
Applications from citizens of the following countries may take longer than 3 weeks (not including mailing time) for processing.
Afghanistan, Bosnia, Iran, Iraq, Kosovo, Lebanon, Libya, Macedonia, Montenegro, Pakistan, Saudi Arabia, Serbia, Somalia, Sudan, Syria, and Yemen. The same waiting period also applies to holders of travel documents issued by the Palestinian Authority or Jordanian documents for Palestinian citizens. [Source: http://www.uwindsor.ca/isc/trv]
I've been a University of Windsor student and dealt with these on several occasions. On emergency situations, you can also extend your TRV in your home country. Normally, it's much faster than here.