The metric of 'Productivity' is the average number of passengers on a bus during one hour. The CTA says, ideally, that'd be between 35 and 55 customers on a bus. Below, we've mapped out the most productive and least productive routes according to CTA data from 2015.
The five most productive routes are indicated in red.
The five least productive routes are indicated in blue.
See our related story about what it would take for the CTA bus system to break even.