Space needed to accomidate 1,200 cars for just a minute or so

This Hot Wheel track really got me thinking about how to model real life commuting. Imagine enough track so the average car takes a half hour from beginning to end and you get and insanely large amount of track. Now think about just 24 buses on this track and the extra wasted space. Seriously think about how much space is needed to accommodate everyone driving single occupancy vehicles verses denser forms of travel.