The tragic sinking of the Sewol ferry has set off alarm bells over society’s safety problems. Not only the government and politicians but also businesses and individual citizens have been making a fuss over safety issues. There is a lot of talk about how to make the nation safer.

But the string of accidents that occurred after the Sewol sinking demonstrate that all the fuss was only in words. Korea is not learning lessons even from this devastating accident.

The collision on Seoul’s subway Line No. 2 last Friday could have been prevented as had been the Sewol calamity had those responsible for the safety of the mass transit system been faithful with their job. It is unnerving that the operator of the subway line, Seoul Metro, was as easygoing and negligent as it had been in the wake of the Sewol tragedy.

It is fortunate there were no fatalities, thanks in part to the driver’s successful effort to reduce the speed of his train as it rammed into the rear of another train at Sangwangsimni Station.

The preliminary investigation into the cause of the incident has made us restless. Investigators said the primary cause of the accident was a failed signal system, which Seoul Metro staff had known about 14 hours before the accident, yet took no action.

There were also problems with the station’s automatic train stop system. The ATS, designed to keep a safe distance between trains, is supposed to activate when trains are within 200 meters of each other. But it didn’t function properly at the time of the incident.

What we find much harder to understand is that the driver of the first train had informed neither the Seoul Metro control room nor the driver of the second train of the 90-second delay of his train’s departure, which was caused by malfunctioning safety screen doors at the station.

All these point to the fact that “human error” contributed to causing the incident, which, like the Sewol sinking, could have been prevented. The Seoul subway incident again exposed safety problems with our mass transportation system.

The subway incident was preceded by a series of safety mishaps in the past week. Two ships, one with 140 people and the other with 390 people aboard, experienced engine trouble at sea. About 10 people suffered injuries when a cable car in Daegu lurched after showing mechanical problems previously.

Then an Asiana Airlines flight bound for Saipan ignored a warning message on one of its engine filters after taking off from Incheon International Airport. It flew four more hours to its destination. It truly was an act of reckless bravado.

All these recent incidents happened at a time when virtually the entire nation has been on its highest-ever safety alert in the aftermath of the Sewol ferry disaster. All the on-the-spot safety inspections that authorities like Seoul Metro conducted turned out to be superficial.

Indeed, Seoul Metro started special safety checks on April 17, one day after the Sewol sank, which lasted until April 30. We wonder how differently the safety checks elsewhere proceeded.