Bunching data are calculated as an average of performance during weekdays between the hours of 10am-4pm, for the months of October 2015 and May 2016. These two months are selected because they contain minimal holidays, mild weather (minimizing service disruptions), and fall during the school year. Speed data are calculated for October 2015 only.
Bunching is defined as the percentage of buses that arrive at less than 25 percent of the scheduled interval behind the previous bus. So if Bus #2 is scheduled to arrive eight minutes after Bus #1, but instead Bus #2 arrives less than two minutes after Bus #1, then Bus #2 is considered "bunched". Bus arrival and departure times are estimated using an algorithm developed by Nathan Johnson and applied to the MTA's Bus Time data. More information about Bus Time data is available here.
Speed is calculated using the same Bus Time data in conjunction with route length information gathered from the MTA's publicly provided GTFS schedules. As presented here at the route level, the travel time from start to finish is simply divided by the route's length to calculate average speed. More details available in the performance API documentation.
Ridership data are for the average weekday in 2015, as reported by MTA New York City Transit here.
Change in ridership data show change in the average weekday ridership from 2010 to 2015. Routes Q50 and Bx23 have been removed from the change in ridership analysis as they were re-introduced in September 2014 to replace the QBx1 and did not have a complete year of ridership data in 2010.
For more information or for access to archival data via an API, please email info@busturnaround.nyc.