Further to last week’s post, I’ve produced a set of plots showing bus locations vs. time for the 66 Chicago bus route. These handily show where delays and bunching occur along the route.
The plots are generated by polling the CTA Bus Tracker API every minute and plotting the position (‘pdist’) of each bus along its assigned route over time. The pdist variable is offset for the various patterns associated with a route in order to compare all route patterns on the same plot. Line segments are omitted for any gaps in the data greater than 5 minutes apart or for bus speeds greater than 70 mi/hr. Given that the GPS location of CTA buses are not reported with 100% reliability, some buses either do not show on the plot or transmit unreliable positions. Large gaps in service shown on the plot may or may not be real, however bunching is real.
More plots and comments on them will be posted next Sunday.