On a normal day, it takes me 35 minutes to bike vs 15 minutes to drive. However, I work on a campus with very limited parking, and my best option is a public parking ramp close to the building I do most of my work. I have driven there only to find out there's an event at the arena (usually sports, but sometimes a rock concert or political rally), and it is impossible to park in that ramp or anything else close by. So I end up driving a few blocks away and end up having to walk, which makes it longer for me to reach my destination. With my bike, I'm guaranteed a dependable arrival time, which is most important to me.