According to this KBOI2 article, Boise commuters spend 16 hours a year stuck in traffic.
It's probably safe to assume that about 15 minutes per week is the time directly attributable to traffic delays - you know, sitting there and looking at somebody's bumper. On top of the amount of time it would take to drive from Point A to Point B, assuming a free flow of traffic.
And Boise's traffic is merciful, compared with Los Angeles (61 hours) or Washington, DC (67 hours). The national average is 38 hours.
On those rare occasions when I have to drive a car in town, I find that sitting in traffic is one of the most stress-inducing things about driving. I just sit there and stew about the time and gas I'm wasting, and find myself longing to be on my trusty velocipede. In fact, if I can tell I'm going to be sitting for awhile, I'll turn the motor off. At least I'm not wasting gas for those seconds.