Starting next July, London's public transport company, Transport for London (TfL), will begin tracking all the smartphones of underground passengers. The phones, and therefore the movements of their owners, will be detected anonymously by the WiFi access points installed in about 260 stations. According to TfL, the initiative will make it possible to better understand passenger flows on trains and in individual stations, offering new information to improve the service, especially during rush hours when hundreds of thousands of people move.
The system is based on MAC (Media Access Control) addresses, a unique code that identifies each device that connects to a local network. When they have WiFi on, smartphones automatically send their MAC address to access points when they search for available networks. TfL explained that the system will work entirely anonymously: the MAC addresses will be converted into an identifier (token) from which it will not be possible to trace the smartphone to which it refers; no other data will be obtained from mobile phones. Additionally, popular operating systems such as iOS, Android and Windows use random MAC addresses when searching for networks, making identification more complicated.
By tracking smartphones from station to station, TfL will be able to better analyze the habits of passengers on the London Underground, as well as having more accurate real-time information on the number of people in its network of trains and stations. The public transport company is already partially able to do this by analyzing the tickets, used in and out, but the data it obtains is less refined than that which will be obtained from the movements of smartphones.
Real-time information on traffic and any congestion of the various lines can be disseminated through the London Underground application, on screens in stations and in the future through applications of some partners, such as Google with its Maps service. TfL also explained that the system can be exploited to better understand which parts of the most popular stations are, improving the yield of advertisements and differentiating the rates for those who want to advertise.
TfL will activate the system on July 8th, but in recent years it had already carried out some tests. In 2016, for example, he experimented with tracking for four weeks, involving 5.6 million mobile devices and obtaining data on 509 million sessions. Once active, the service will raise billions in just a few months.
The proposal to trace millions of smartphones had initially perplexed the organizations that deal with the protection of privacy. TfL then came up with its own project by working together with the Information Commissioner's Office (ICO), the UK's privacy supervisor. The system for anonymizing MAC addresses has been approved and it is not believed that there will be any contraindications. In any case, information panels will be displayed in the stations, with warnings on the system and advice on turning off WiFi if you do not want to participate.
