Compute hourly bus counts per street segment

[thcrock]

John reports that a threshold used by LA for deciding that a road segment should get a bus upgrade is 25 buses passing by in an hour. We would like to identify all of the road segments where this is true. The CTA's GTFS data defines when trips are scheduled and the sections of road where they go. Without any ridership data, we can compute the number of buses on each stretch of road at any one time.

We can work on the actual deliverable to tell people about these segments later (map? list? upload the raw data to OpenGrid?), but the deliverable of this issue should probably just a be a CSV. Each row lists the segment, hour, and # of scheduled buses