The on-board congestion information system introduced to solve the overcrowding of subways in the Seoul metropolitan area, which turns into a so-called “hell season” during weekday rush hours, is causing confusion among passengers. As the issue of overcrowding in subways such as the Gimpo Gold Line has become a hot topic, it is pointed out that the management of congestion on trains needs to be reviewed.

According to the Seoul Metropolitan Transportation Authority on the 21st, subway congestion is calculated based on the capacity of one subway car (60.84㎡), and if 160 people are on board, it is calculated as 100% congestion. Slow (80% or less) and moderate (80-130%) stages allow for easy movement, caution (130-150%) means inconvenience, and congestion (150% or more) means that movement on the train is impossible.

A view of the Jamsil-bound train on Subway Line 2 on the afternoon of the 16th. It was cramped to the point where it was inevitable to come into contact with other passengers when trying to move to another car, but the congestion level displayed on the train monitor was “relaxed.”/Photo=Yoo Byung-don Reporter TAMOND@

Recently, subway safety issues have been raised, such as the Gimpo Gold Line, which has a 200% overcrowding rate, and the level of crowding in subways has received renewed attention. In fact, there have been a number of cases of people complaining of breathing difficulties on the Gimpo Gold Line. On December 11, a teenage high school student and a woman in her 30s collapsed at Gimpo Airport Station, complaining of breathing difficulties, and 119 paramedics were dispatched, and on December 21, a woman on the train was taken to the hospital after complaining of breathing difficulties.

As a result, passengers are increasingly interested in a system that allows them to check the congestion level of each car before boarding the subway. Subway Line 2, in particular, has been operating new electric trains that display the congestion level by car since 2019. This has not yet been applied to other lines, but you can check the congestion level using smartphone applications.

However, there are complaints that the congestion measurement is often inaccurate, and the criteria itself does not reflect the density. In fact, when I rode Jamsil on Subway Line 2 on the 16th, the car was already full and crowded with standing passengers. When I tried to move to another car, it was cramped to the point where I had to touch other passengers, but the congestion level on the train monitor was “free”.

We believe this error stems from the way crowding is measured. Each car is equipped with a weight sensor to detect and measure the weight of passengers in real time, which is not suitable for measuring crowding. The Seoul Metro explained that it calculates the number of people by multiplying the measured load per compartment by the average weight of 65 kilograms per person. However, according to the National Statistics Portal, the average weight of South Koreans as of 2020 was 74.5 kilograms for men and 58 kilograms for women, which is a large margin of error based on gender alone. Add to that the elderly and obese population, and the error is even greater.

“The most reliable way to measure how many people are in a train compartment is visual judgment, but this is not possible in reality,” said Lee Young-joo스포츠토토, a professor of fire and disaster prevention at Seoul National University, adding, “We are researching and developing several technologies that can determine density through video.” “It is meaningful to provide real-time information on congestion, but it would be more efficient to quickly inform passengers of such hazards in the event of unusual overcrowding, rather than routine,” Lee said.

In response, the Seoul Metro explained, “The congestion level displayed in real time in each train compartment is probably different from the visual congestion level because it is done by detecting the load.” “We are also operating a method to analyze the congestion level by linking the total number of passengers identified by the transportation card data with the data of mobile communication devices installed in each subway compartment.”