The city of Helsinki recently set up a new site showing the density of people present in its most frequented districts and streets in real time. This kind of tool could be used in the future in other large cities to help people plan their trips, avoiding crowded areas.
To make this possible, the Finnish capital has installed numerous sensors in all locations, with a strong focus on the city center and the areas that are usually the most popular with tourists. The data is collected from the Bluetooth signals of connected mobile devices, starting with smartphones.