In February, police caught a 25-year-old nightclub employee who stole a car of one of his customers by tracking the location of his mobile phone, just seven hours after the theft.
Police are also able to monitor the use of chip-embedded credit cards, used for cashless payment on subways and buses. The cards record the movement of the user, and track the IP addresses of computer users suspected of criminal acts.
Critics are also voicing concerns over Seoul City's traffic-control plan based on installing electronic devices in passenger cars to track their movements.
Since the start of the year, the Seoul Metropolitan Government has been granting a 5 percent discount in automobile taxes and a 2.7 percent discount in auto insurance fees for drivers participating in the 'No Driving Day' campaign, which requires them to leave their vehicles at home for one day a week.
The drivers participating in the program are required to install electronic tags on the front windows of their cars, which allows traffic authorities to track their movement.
The electronic tags attached to cars, enabled with radio-frequency identification (RFID) technology, will broadcast information from the cars to readers the authorities have installed at major traffic points in the city.
Although city authorities had been downplaying privacy concerns, stressing that participation in the programs are strictly voluntary, many residents complain of being pressured by their ward offices to attach the electronic tags to their cars.