Transport chiefs should put themselves in the position of passengers when assessing the performance of bus companies.
That is according to an Ombudsman's report released yesterday that criticises officials for failing to deal adequately with a growing number of complaints.
The watchdog highlighted a large discrepancy between the way the Transport Department defined "lost trips" and how passengers defined them.
It said the department only counted the total number of trips on a route and compared this to how many were required. But delays caused to passengers by irregular services and buses skipping stops could also be viewed as constituting "lost trips".
"The Transport Department should consider bus operators' service quality from the passengers' point of view," Ombudsman Alan Lai Nin said.
The number of complaints about irregular services more than doubled from 3,080 in 2011 to 6,993 the following year. But at the same time the number of lost trips - as calculated by the Transport Department - fell.
The lost trip rate of New World First Bus rose from 3.1 per cent in 2011 to 4.7 in 2012, but fell to 2.6 last year. That of Kowloon Motor Bus fell from 8 per cent in 2011 to 4.6 in 2012, then to 2.8 last year.
Lai said the rates would be much higher under the public's definition of a lost trip.
The report also criticised the department for only warning bus companies without punishing them and for unsatisfactory replies to complaints.
The Ombudsman's investigators conducted two site inspections and found that 26 per cent of the 537 bus trips on more than 10 routes were delayed A fifth of the buses on three routes left the terminus later than scheduled in the first half of last year.
The Transport Department attributed the lost and delayed trips to a shortage of bus drivers, too few buses and traffic congestion. The Ombudsman said it was the department's responsibility to tackle congestion, such as by tightening enforcement on illegal parking.
Lai said the bus companies should consider using a global positioning system.
The department said it would review its definition of lost trips and discuss with bus companies how it could be calculated in different periods of a day.
It will consider verifying operational data provided by the companies and reviewing the department's disciplinary system.
Kowloon Motor Bus said it suffered from a loss of manpower after the introduction of the minimum wage in 2011 made jobs in building management more attractive.
It suggested the government measure average bus speeds, monitor the time it takes for a trip and increase routes accordingly.
New World First Bus and Citybus said they had been facing difficulties in recruiting drivers.