When you absolutely must...
...tell the world that you drive like a complete jerk, fasten one of these to your front bumper!
Mary and I were running errands yesterday. We left the neighborhood and started north on the frontage road, a two lane with a 35 mph speed limit. Within half a mile, a guy in a small car was quite nearly in our trunk. He was close enough that I couldn't see his headlights in my rear view mirror. When I slowed to turn into a parking lot, he passed us in the dedicated left turn lane.
Motorists routinely complain about 'arrogant' cyclists taking the lane and how they must feel superior somehow. But when it comes to having a sense of entitlement, a God-given absolute right to drive as fast as they wanna whenever they wanna, it's hard to compare cyclists to motorists like this one.