Here is information from a budget-minded traveler about public transit bus service from Detroit Metropolitan Airport (DTW) to downtown Detroit. Page was created after a personal experience on September 25, 2004, with information updated on December 24, 2013 using the web and some feedback comments emailed to me. This travel option is not well described at the airport! I suggest making a copy of this page or the Metro Airport page describing where the SMART route 125 bus stops for pick up at the airport. If you try this option, send feedback to me at email@example.com, especially if this page contains errors or needs improvement.
SMART Bus route 125 is the lowest price option for getting from the main Detroit (Wayne County) Metropolitan Airport to Detroit area destinations. The fare is now (October 2013) $2.00 (cash, exact change, dollar bills accepted but not dollar coins). Fare page is http://www.smartbus.org/faresandpasses/overview/Pages/default.aspx.
Go to this SMART Bus web page for the schedule of route number 125: http://www.smartbus.org/schedules/overview/Pages/default.aspx. On this page you have to use drop-down menus to choose Route 125, weekday or weekend, and direction. From the Airport to downtown Detroit is North.
Unfortunately, the 125 bus goes all the way downtown only in peak periods. At some times of the day, you will have to transfer to or from a Detroit Department of Transportation (DDOT) Route 25 bus at Outer Drive & Fort St, only about half way to downtown Detroit. The schedule for this bus is at https://www.detroitmi.gov/Portals/0/docs/deptoftransportation/New_Bus_Scheds/green/25JeffersonMS.pdf.
And to make things complicated, there are other route combinations that work to get you to and from the Detroit Airport.
All told, the best advice now is to use the Google Trip Planner for exact times and bus numbers in your planning. Go to http://www.google.com/intl/en/landing/transit/ and enter Detroit Metropolitan Wayne County Airport as your starting point, plus your Detroit destination such as the name of your hotel. Another gateway into the Planner is http://www.smartbus.org/Pages/default.aspx.
A taxicab or rental car takes about 30 minutes from the airport to downtown Detroit, but costs much more. Unlike most U.S. airports I have seen, Detroit Metro Airport offers no reasonably priced express bus option for downtown Detroit hotels as of late 2013. The SMART Bus option is described on the Metro Airport web page http://www.metroairport.com/GroundTransportation/PublicTransit.aspx.
Route 125 buses leave the Detroit Metro airport for downtown approximately every 60 minutes on weekdays, from both the (older) L.C. Smith Terminal, and the (newer) McNamara Terminal that serves Delta and Continental Airlines. An international traveler who used this bus in late 2013 wrote me, "The best thing to tell people is that the stop in McNamara terminal is the same stop as the employee transportation bus and that it's best to follow the signs for 'International Arrivals.' It's on the lowest level but it's not where you would get the hotel shuttles. If you wind up there, turn around and look through the windows across the "street" to another picking up area. You belong over there but you have to go up again, over and down again to get there."
Check the schedule for which terminal is served when, and for the different weekend schedule. If you just miss the bus at one terminal, you could take the available free shuttle to the other terminal and catch the route 125 bus there that leaves 30 minutes later than the one you just missed.
In downtown Detroit, the bus driver if asked will (probably) let you off near a People Mover station, an elevated circulator transit system that covers the downtown area. The SMART Bus network also has routes to other places in the Metro area. System maps are at http://www.smartbus.org/schedules/maps/Pages/default.aspx.
Happy (and economical) travels! Enter feedback about the information on this page to firstname.lastname@example.org.
One more thing -- there is an interesting social characteristic of transit riders in Detroit -- quite often all of the passengers on a bus, including the driver, get into a friendly but lively conversation about some topic of general interest -- the weather, sports, or some prominent news story. I've experienced this, and another visitor to Detroit confirmed that this happens frequently.
You've been reading an unofficial, one-off information page at www.bettertransport.info that is only found easily via Google or Bing searching. Go to the SMART Bus website for the latest information on the downtown to the airport bus in Detroit. The Wikipedia page for the SMART system is http://en.wikipedia.org/wiki/Suburban_Mobility_Authority_for_Regional_Transportation.