Urban mobility studies are critical to acquiring insights about traffic management, urban mobility evolution, planning of urban spaces, and many other applications. However, the study and mitigation of recurrent problems have been postponed in real cases, given the difficulty of gathering mobility data. This paper presents a method to detect potential hazard driving zones. We mapped bus GPS positions into road segments, and we used bus speed, bus maximum allowed speed, and bus acceleration to classify the driving behavior. We develop an interactive web application that maps tracking data and provides rich visual insights on potentially problematic areas.Side-by-side visualizations help with the comparison of the traffic behavior in selected periods. We show that we can map the most problematic zones in the city and the time of the day. From the developed analysis, it is observed that some roads in the city present a daily seasonality (problems occur in the same period of the day); however, other roads present circulation issues independently of the time period or day.