Nationwide Insurance says traffic jams cost the average motorist $716 per year. According to their interesting chart, the worst city is Washington, DC, where people spend 72 hours per year sitting in traffic jams. Frankly, that seems low to me... as somebody who occasionally sits in big-city traffic, I'd think the accumulation would be more than 10 or 15 minutes per day.
The most prevalent causes of traffic jams? Bottlenecks (40%), traffic incidents (25%), bad weather (15%), work zones (10%), poor traffic signal timing (5%).
I'd say cyclists are pretty much immune from all of those but bad weather. And I've been slowed by bad weather on my bike, but never "traffic jammed."