When do the majority of pedestrian fatalities occur?

The majority of pedestrian fatalities occur at night due to decreased visibility. This is a critical factor as it impacts both drivers' ability to see pedestrians and pedestrians' ability to be seen by drivers. Poor lighting conditions can lead to a higher likelihood of accidents, as drivers may not detect pedestrians until it is too late to react.

While it's true that unexpected movements by pedestrians, such as suddenly running into the street, can increase the risk of accidents, the overarching pattern shows that many pedestrian fatalities happen under reduced visibility conditions, predominantly at night. This highlights the importance of both pedestrians and drivers being extra cautious during nighttime driving or walking.

In terms of the other options, bad weather can contribute to accidents, but it is not the most common time for pedestrian fatalities. Busy urban areas tend to have more pedestrians, which may increase the number of accidents overall, but not necessarily fatalities, as other factors come into play in those settings.