Nowadays, it is very common to use solutions based on Bluetooth and WiFi technology (hands-free kits or Internet access routers) in cars.
A large group of cars in the whole communication stream, equipped with such elements, gives the possibility to study its structure. By knowing the distance between the places where the detectors are installed, we can calculate the speed of the passage and run a whole apparatus of analysis, showing the formation of congestion, illustrating the behaviour of drivers, indicating violations of the law and worsening road safety. We can also find the relationship between air pollution and the traffic structure studied. An even more interesting idea is to install such solutions with an additional GPS module, e.g. on public transport. In this case, we gain a city scanner, which shows us environmental pollution and the traffic structure at the same time! Every tram and bus can work towards understanding the processes occurring in the urban environment. It is important, due to personal data protection, that the Enviro-251 system can mask all or part of the MAC address. This prevents the event stored in the database from being assigned to a specific mobile phone number.