Task: Question Answering
Input (English): Context: It is easy to see why motorcycles are appealing to a large number of people , old and young alike . These vehicles are great for heavy daily commutes because they are small and maneuverable , making it possible to weave in and out of traffic and split lanes to get ahead of the crush of cars that are otherwise stalled . This practice is not only legal , it is encouraged as a method of relieving congestion and getting at least a few motorists off the roads faster , hopefully cutting down of pollution as well . 
Question: why are the cars all stalled ?
Output (English): because of congested traffic.