My commute is similar to yours:
Car (usual) - 5.5 km - 12-20 minutes
Biking (~ 12 times/year) - 5.5 km - 20-25 minutes
Running - My route takes me over a busy highway and the fumes kill me. Okay for biking but running is gross.
I used to work downtown and didn't own a car, I took transit or biked. I now work in a suburb off the main transit routes and it takes me three times as long to bus than to drive. Add to that getting to my workouts way on the other side of town after work became impossible so I caved and bought a car.
AutomaticJack wrote:
Car (Normal): 4.5 miles - 15 to 25 minutes
Biking (about a dozen times a year): 7.5 miles - 35 minutes
Running (Once in a while): 6.2 miles - 50 minutes
The distances vary because the most direct route is very dangerous for a bike or to run. Running is shorter than the bike because I can cut through a shopping center and golf course.