Biking in the snow / slush (especially on public streets since Detroit doesn't have the money to clear sidewalks) is an extremely precarious proposition.
[1] http://www.amazon.com/Effective-Cycling-John-Forester/dp/026...
http://www.mrmoneymustache.com/2011/11/03/how-to-ride-your-b...
So apparently half of the problem is that Oakland county doesn't have as much public transit as Wayne county.
For the unaware, the 'Somerset Collection' they mention in the article is a mall with Cartier / Burberry / Salvatore Ferragamo stores inside. There's a certain amount of symbolism that the Detroiter has to commute past vast affluence that was once local to Detroit to chase a factory job.