I ran across a r*dd*t subforum in r/f*ckc*rs called "This weekend 18.000 people in #Muenchen kindly demonstrated to decision-makers how to easily optimize throughput. Traffic engineers, you're welcome!"
It took 18,000 people on bicycles to clear a specific section of a highway approximately 1 hr.
I asked if there were any data showing how long it would take for 18000 people in motor vehicles to clear the same section of the same highway. I got a discussion involving assumptions that would go into traffic models. However, since this is an existing highway, I would be certain there should be real-life data for what I was asking.