Increased use of public transport

There is this big hoohah about the increase in the use of public transport in Singapore. Apparently, subway use has increased by 6%, while buses by 4%. The authorities cite the reason as rising oil prices.

Wait.

Can we make such conclusions just by looking at numbers? After all, many many factors can contribute to the increase in the use of public transport. Oil prices can be one reason. What about an increase in the awareness of conserving energy? Maybe people do care for the environment, and therefore drive less and use public transport more? Or it could be due to rising COE prices, which means it is harder to buy cars, and thus people stick with public transport (and with an increasing population, that means an increase of public transport use).

I think we are so fixed in our mindsets that all events have a cause, that we fail to realise that sometimes, an event can have multiple causes. Unless we survey the people who take public transport for their reasons, we will not know why there is an increase, so we shouldn't jump to conclusions that it is due to rising oil prices.