Two police officers of Shanghai Hongqiao Railway Station analyze the data mapped on the screen. (Ti Gong)
Shanghai Hongqiao Railway Station has introduced a web-mapping system which visualizes the density of the crowd at the station so that authorities are better prepared for "big-crowd emergencies," Shanghai police said on Wednesday.
This railway station is the first in China to be equipped with the technology which is based on tracking of people's mobile devices when they're connected to the internet, police said.
Police officers at the command center of the station look at a large screen which shows the density of the crowd in the station's waiting area in the colors of green, yellow and red with red signifying the greatest density.
The system collects data of media access control addresses (MAC addresses) from mobile phones, which serve as unique identifiers of the mobile devices on the internet, and maps the density of the addresses, police said.
Based on the data, the system can also count the real-time number of people at the station.
Police didn't reveal the "threshold number" beyond which emergency measures come into force to manage the big crowd, but said they also look at surveillance cameras before taking any decision.
Emergency measures usually mean that more police officers are put out for patrolling the station and for crowd control.
Hongqiao as well as other train stations in Shanghai will likely see bigger crowds than average during the upcoming annual chunyun season around the Chinese New Year in February, when migrant workers leave Shanghai for home.
About 180,000 passengers go through Hongqiao Railway Station daily, and the number could hit 260,000 on peak days.