The city has hired too few inspectors to catch fare-dodgers and motorists who stray into bus lanes (though cameras are catching some of the errant cars).
Sometimes buses are so crowded that even honest passengers have trouble reaching the card-swiper.
Increasingly, passengers are less inclined to pay.
Despite the subsidies, fares have risen by 40% since 2010, far faster than most prices.
Bus journeys have slowed by 8% since 2012.
For some, fare-dodging is a form of protest.
Guillermo Munoz, the metropolitan area's director of public transport, admits that in some parts of the capital the service is “very bad”.
Last month Chile's transport minister resigned, in part to take responsibility for Transantiago's failings.
Espacio Publico says one reason for the high subsidies is that too few companies operate the buses.
The system began with 16 operators but dropouts and mergers have shrunk the number to seven.
The largest firms operate 1,200 buses apiece.
This makes them “too big to fail”, says Clemente Perez of Espacio Publico.
Espacio Publico智囊机构的Clemente Perez谈到，这使得这些运营商“规模太大以至于不会破产”。
Hence the subsidies to keep money-losing companies afloat.
No company should have more than 10% of the market, Mr Perez thinks.
The city will have a chance to correct that next year, when contracts to operate bus lines are to expire.
It is likely to encourage smaller and newer companies to enter the market.
That might release money for improvements.
The new transport minister, Paola Tapia, has created a task-force to help reduce fare-dodging and promised more money for inspectors.
With luck, Transantiago could become a service that commuters are happy to pay for.
1.in part 某种程度上；部分
例句:The levels of blood glucose depend in part on what you eat and when you eat.
2.pay for 赔偿
例句:I have had to pay for repairs to the house.
3.take responsibility for 对...负责
例句:We need to take responsibility for looking after our own health.
4.have a chance to 有机会...
例句:If we divorced, I would have a chance to hold a wedding for you again.