Why is the Bus Always Late?

German newspaper Tagesspiegel has been investigating the punctuality of Berlin's buses, trams and subway trains. They wanted to know which lines, bus-stops and stations had the best and worst punctuality problems. They also wanted to know why some buses are always late and why some trams are always on time or even early.

Why is the Bus Late? includes an interactive map which allows you to explore the punctuality record of every stop and station on Berlin's public transit network. Select any transit line on the map and each station on the line will be shown with a small graph showing how often the buses, trams or trains are on time, early or late. You can select a station on the map to view the exact percentages. You can even change the direction of travel to view the punctuality of the vehicles travelling in each direction on the line.

It turns out that trains in Berlin are pretty good at arriving on time but buses are often late. Why are the buses often late? It's all the fault of the trains.

Apparently when the train lines are forced to close, for maintenance or for emergencies, replacement bus services are provided for the train passengers. This takes buses and drivers away from the normal bus routes. Therefore one reason that buses sometimes run late in Berlin is because they are covering for the trains.