Of the 26,000 calls made to the hotline since October last year, 18,800 were about poor taxi services, 1,600 related to problems with non-air-conditioned buses and 1,400 were about public passenger vans, a department source said.
A further 1,200 complaints related to privately owned air-conditioned buses operated under contract with the Bangkok Mass Transit Authority (BMTA), while 1,200 callers aired grievances with services run directly by the BMTA.
Another 200 calls were from people unhappy with motorcycle taxi services. The rest related to motor-tricycle and songtaew truck operators.
The source said the department has processed 94.1% of the complaints. For the rest, officials are inviting drivers for questioning.
Most of the taxi complaints were about drivers refusing to take passengers, followed by impoliteness and reckless driving, the source said.
The most common complaint about passenger van services related to reckless driving, followed by drivers refusing to stop to allow passengers to get out when requested. There were also many complaints about rude drivers of passenger vans, said the source.
Department director-general Achasathai Ratanadilok na Phuket, said people who were inconvenienced by public transport service operators would soon be given more channels to file complaints.
In addition to the telephone hotline, the department plans to accept complaints via text message and smart phone applications, he said.
To increase efficiency in investigating passenger complaints, the department is also considering opening a new database centre to keep records of all public transport drivers, Mr Achasathai said.