How we measured
The transport company publishes the live position of every bus as open data. From 1 July to 30 September we stored the arrival time at each stop and compared it with the timetable. A bus counts as late when it arrives more than three minutes after the scheduled time, the same threshold the company uses in its own reports.
What the data shows
Across all city lines, 81 percent of trips were on time. On line 12 it was 34 percent. Almost all of the delay builds up on a 900 metre stretch between Marktplatz and Brückentor, where the bus shares a single lane with delivery traffic between 7 and 11 in the morning.
Afternoon trips on the same line are on time in 72 percent of cases, close to the city average. That rules out the timetable itself as the main cause.
What could change
A bus lane on that stretch has been proposed twice and rejected twice, most recently in 2023. The transport company estimates it would cut the average delay on line 12 from six minutes to under two. We share our dataset and method with anyone who asks through the contact page.