Parking

TODO: Fill out the types of parking available, public/private, blackholes, how people pick spots, how seeding works, etc.

Infinite parking

If you pass --infinite_parking on the command line, every building gets unlimited public spots. This effectively removes the effects of parking from the model, since driving trips can always begin or end at their precise building (except for blackhole cases). This is useful if a particular map has poor parking data and you need to get comparative results about speeding up some trips. Often the A/B testing is extremely sensitive, because a parking space close to someone's destination is filled up quickly, slowing down the trip.