After a few delays, the test run of the much-awaited Mahai Sawan underpass since late September has become a boon for commuters and somewhat of a headache for residents in Thon Buri district.
Thongsai Seedaluang, 36, who commutes to work daily along Taksin Road, said traffic during rush hour has eased following the soft launch of the Mahai Sawan underpass. Taksin Road is crowded with cars and public transport vehicles as it connects Sathon, Phetkasem and Rama II roads.
He called on the government to be more serious and considerate about road works, saying the project has had planning and scheduling problems, that caused delays and inconvenienced commuters when the work was under way.
Started in 2011, completion of the supposedly two-year project has been delayed for more than three years. Next March will hopefully mark the end of the long-awaited Mahai Sawan underpass project in Thon Buri district as it is set to officially open to traffic.
Chattaphum Ekkapopwasin, 60, whose house is located near the Taksin area, echoed Mr Thongsai's concerns, saying the traffic has been terrible during the construction of the underpass.
He urged the government to consider constructing more footbridges near the underpass, saying they will help improve pedestrian safety, particularly for young students whose schools are near the underpass.
A resident, who asked not to be named, said the underpass will have a negative impact on businesses nearby.
There are no spaces for parking cars in front of shops as a result the construction, discouraging potential customers from going to the shops, the resident said, adding that business has slowed over the past few years and the project will only make the problem worse.
The unnamed resident urged the government to help solve the problems, saying the project has forced some entrepreneurs to close their businesses because of heavy financial losses due to fewer customers.
However, observers say the project is worth waiting for as it has helped ease the travel pain for road users by reducing the area's notorious traffic levels during the trial-run period.
Deputy Bangkok governor Chakkaphan Phewngam said the asphalt surfacing and system test run is under way. Pavement work and traffic signs are expected to be completed by February.
He confirmed the underpass will be fully operational on March 1, 2017.
At 887 metres long, Mahai Sawan is the city's longest underpass and is parallel to Taksin Road which intersects Ratchadapisek Road, one of the city's busiest roads.
Most other underpasses are about 400 metres long.
The four-lane underpass is expected to ease traffic problems and divert traffic from the inner city.
Chiradeth Karunkitkul, director of the Public Works Department's Construction Supervision Division, said the Mahai Sawan underpass is one of eight traffic projects initiated by the Bangkok Metropolitan Administration (BMA). They are aimed at minimising traffic problems in different areas of the city.
The Mahai Sawan project was passed by the Commission for the Management of Road Traffic in February 2004, he said.
The BMA signed a contract to hire Krung Thon Engineers Co Ltd to construct the underpass with a budget of around 97 million baht. Construction work began on Oct 11, 2011 and was expected to be completed in two years.
But the work was delayed for more than three years, with five time limit extensions, he added.
On Aug 8, 2012, the cabinet approved a 180-day delay because the area was affected by floods, bringing work to a temporary halt.
Two years later, the government's 300-baht minimum daily wage policy and technical work around the project impeded work progress. The problems prompted the cabinet to approve another 150-day contract extension.
In 2014, work was again interrupted because of the removal of electrical poles nearby. This resulted in a further delay of 288 days.
Technical problems also slowed progress in 2015, forcing yet another delay -- this time for 256 days.
Last April, the project was delayed once more due to design-related errors and concrete piling problems, according to Mr Chiradeth.
The BMA chose to build an underpass despite a flyover being three times cheaper because there were several footbridges in the vicinity.
"We did not think it made sense to build an intersection flyover. We thought it would be dangerous to build a flyover that would have to be higher than the existing pedestrian bridges," Mr Chiradeth said.
He said automatic lighting installation work is under way and expected to be finished this month, adding lighting is currently being operated manually.
A smart lighting system is being implemented in the underpass as the technology comes with automated controls and can make lighting adjustments based on conditions and occupancy and the availability of daylight.
The underpass opened for a test run on Sept 30 with the construction work some 90% complete. It is open to traffic from 5am until 10.30pm, after which it is temporarily closed to allow the remaining work to continue.
Motorcycles and cars are allowed to use the underpass with a speed limit of 50km per hour, Mr Chiradeth said. Heavy trucks, buses and coaches are banned.
Jinnawat Kontongdee, the superintendent of Bukkhalo Police Station said his officers who direct traffic near the underpass have told him it has helped reduce the area's notorious traffic levels during rush hour.
In the past, heavy traffic saw 50,000-70,000 cars pass through the Taksin Road and Wong Wian Yai intersection each day, he said.
However, police have found it would not be safe for motorcyclists to use the underpass since the lanes are slightly narrower, Pol Col Jinnawat said.
After the underpass is officially opened, he said he would submit a letter to the traffic police, asking them to consider banning motorcyclists from using it, citing safety reasons. This regulation is expected to be enforced 30 days after it is approved.
Mr Chakkaphan backs Pol Col Jinnawat's idea to ban motorcyclists, saying: "We are not discriminating against motorcyclists, we are only concerned about their safety."