I live off of campus in lincoln NE and my bike ride takes about 11 minutes to and 15 minutes from class. A car would take about 12 minutes plus the time to get from your parking to your class (about 6-7 minutes) so technically the bike is faster. I have a fast and expensive bike however, and I brake a few traffic laws by not using cross-walks. I saved about $300 on a parking permit plus the cost of gas and regular maintenance. In certain situations, biking is faster and much less costly. I will however say that I am consuming literally 1000 extra calories a day.
Also, take a look at this:
http://www.cnn.com/2005/HEALTH/diet.fitness/08/24/obesity.oregon.ap/index.html
Oregon is the only state this year that hasnt gotten more obese.
Basically, biking has improved my cardio, saved me money, and saved me time; unfortunately it keeps me from gaining any weight on my 150 lb frame