Massive Sinkhole Opens on Samsen Road Near Vajira Hospital, Disrupting Morning Commute

BANGKOK – A large and rapidly expanding sinkhole opened up on Samsen Road in Bangkok's Dusit district early this morning, Monday, October 6, 2025, causing the road surface to collapse and creating a significant hazard for motorists. The incident occurred near the entrance of the well-known Vajira Hospital, leading to immediate road closures and severe traffic disruption during the peak morning commute.

Authorities are on the scene to assess the damage and secure the area. While a formal investigation is underway, initial reports suggest that the collapse was likely caused by a combination of a major burst water pipe beneath the road and the effects of ongoing subway construction in the vicinity.

The event began shortly after dawn when a small section of the asphalt reportedly gave way. Witnesses described hearing a rumbling sound before the ground suddenly opened up. The cavity then expanded quickly, swallowing a large portion of the inbound lanes. Images and videos from the scene show a gaping hole with jagged edges of broken asphalt and soil, with water visible at the bottom of the crater.

Metropolitan Police officers were dispatched immediately to cordon off the affected section of Samsen Road, stretching from the Si Yan intersection towards the Thewet intersection. Traffic is being diverted to nearby routes, including Nakhon Ratchasima Road and Ratchawithi Road, but authorities have warned the public to expect major delays and to avoid the area if possible.

"The primary concern right now is public safety," said an official from the Bangkok Metropolitan Administration (BMA) at the scene. "We have secured the perimeter and are working with engineers to determine the stability of the surrounding ground. We cannot allow any traffic, including pedestrian traffic, near the site until we are certain there is no further risk of collapse."

Attention has quickly turned to the two suspected causes. A burst underground water main is believed to have washed away the sand and soil supporting the road surface, a process known as subsurface erosion, creating a void that eventually collapsed under its own weight.

Compounding this issue is the extensive excavation work for a new mass transit line being conducted nearby. The vibrations and potential changes to groundwater levels associated with deep tunneling are known risk factors for ground subsidence. The Mass Rapid Transit Authority of Thailand (MRTA) released a preliminary statement acknowledging the incident.

"We are aware of the road collapse on Samsen Road and are sending our engineering teams to cooperate fully with the BMA's investigation," the statement read. "Our construction projects are carried out with strict safety protocols, and we will work with all relevant agencies to determine the exact cause of this event."

A local shop owner who witnessed the collapse expressed his shock. "I was setting up my stall when I heard a strange, deep noise," he said. "At first, I thought it was just the construction, but then the road simply fell in on itself. It was very frightening. It’s lucky that no cars or motorcycles were passing over that exact spot at that moment."

Engineers from the BMA and the MRTA are now conducting geological surveys to understand the full extent of the cavity and the stability of the surrounding area. A timeline for the repair work has not yet been established, but officials have indicated that the complex nature of the collapse means the road will likely be closed for several days, if not longer.

Motorists are strongly advised to check real-time traffic applications and follow instructions from police on the ground. Access to Vajira Hospital remains open, but visitors and patients are being directed to use alternative approach roads.