Final answer:
The speed limit for alleys and narrow residential districts is typically around 30 miles per hour but can vary based on local laws. The de facto speed limit might allow for slight leeway above the posted speed. Pedestrians should ensure they have enough time to cross the road safely before a car reaches them.
Step-by-step explanation:
The speed limit for alleys and narrow residential districts typically varies based on local laws and ordinances. In many areas, the speed limit is lower than the main roads to account for the limited visibility and narrower space. The specific speed limit can differ from place to place, but a common urban residential speed limit is around 30 miles per hour, which is roughly 50 kilometers per hour.
When considering safety, it's important to note that drivers should adjust their speed for conditions and the presence of pedestrians, especially in residential areas. The de facto speed limit may differ from the de jure limit; the latter is what's legally posted, while the former is the speed at which enforcement is likely to begin. For instance, while the posted speed may be 30 miles per hour, drivers often have a small amount of leeway, e.g., driving at 31 miles per hour might not result in a ticket.
To cross a street safely where cars are traveling at the speed limit, pedestrians should ensure they can walk a distance equal to at least the width of a car plus some added margin before a car reaches them. This is to account for both the pedestrian's safety and the vehicle's stopping distance.