Passengers say they have not seen any significant changes for the better, despite the minister's vow to improve services.
Mr Chadchart insists a survey shows passengers are happier with the service, but those polled by our reporter disagree.
Sawinee Laithaisong, 23, said the condition of the buses is still poor and the service just as bad. She said she would travel on other routes whenever she could since bus No.8 was always packed during rush hours. "I have not noticed any change. It has been the same for the past 10 years. Passengers are lucky if they get a bus with a good driver," she said.
A 40-year-old male passenger who declined to be named said bus route No.8 is important as it passes many handy locations such as department stores, hospitals, markets and workplaces. But the quality of the drivers and the buses' condition are still poor, he said.
Most of the drivers go too fast and often fail to stop to pick up and let off passengers, he said. Many drivers also curse at passengers when they're slow to get on or off. He said the Transport Ministry should improve all bus services in Bangkok, not only route No.8.
"I don't think Mr Chadchart can make a big change to the buses on route No.8. The ministry needs to have a clear policy on how to improve bus services in the capital. It should also employ more inspectors to monitor drivers," he said.
In August, Mr Chadchart rode a bus on route No.8 with a group of reporters after receiving complaints from passengers about its poor service.
Complaints included speeding, bad-mannered fare collectors, buses in poor shape and the drivers' refusal to pick up and let off passengers at bus stops.
The minister said he would order improvements to services on all bus routes, including route No.8.
Buses on the route are privately operated with Bangkok Mass Transit Authority licences. Eighty one buses run on the route, all non-airconditioned.
The route runs from Happy Land in the eastern outskirts of Bangkok to the Memorial Bridge, covering 30km.
Buses on the route run past Lat Phrao Road, Phahon Yothin Road, Victory Monument, Ratchavidhi Hospital, Lan Luang Road and Worajak before ending at Memorial Bridge.
Mr Chadchart said he had surveyed passengers who said the service on the route has improved.
He said he still rode on passenger buses and trains every week to get a first-hand feel for their services.
Incentives have also been offered to bus No.8 drivers and conductors to provide better services.
Four pairs of drivers and conductors have been chosen to receive awards for good service under this programme, he said.
We took a three-hour ride on a No.8 bus from Happy Land to Memorial Bridge on Saturday.
Although the bus travelled at a moderate speed, the driver still allowed passengers to get off the bus in the middle of the road during traffic jams.
The driver also failed to observe the traffic rule which requires him to keep his vehicle to the innermost left-hand lane. The rule was printed on a sticker in clear view inside the bus.
The bus was also ancient. One passenger seat had come loose from the metal pole connecting it to the floor and was secured with rope.
Tawee Summart, 54, the bus driver, said he and his friends have tried to maintain good driving habits but he could not drive too slowly as passengers wanted to get to their destinations quickly.
He said the passengers complain if he drives too fast or too slowly.
He said he often drives at 70kph hour if the road is not congested.
He also tries to avoid racing his bus against others when trying to pick up passengers.
Bus conductor Ekk, 30, admitted, however, it was impossible for drivers to avoid speeding because each bus needs to make four round trips a day to earn enough money to cover costs.
He insisted he always tried his best to please passengers on his bus.