I have been taking the bus daily for the past two years. I also take the bus to visit my doctor and to visit some other places.

I am careful to look at the number of the bus to make sure that I board the correct bus.

Does this mean that I am careful all the time - and cannot make a mistake?

No. On one or two occasions, I got up the wrong bus. It is possible to make a mistake. That is how accidents happen, right?

After boarding the bus, I found that it was making a wrong turn. I checked with the driver and found that I was on the wrong bus.
The bus number was not displayed inside the bus.

I am sure that some passengers make this mistake from time to time. They do not make this mistake every day. But it happens on some rare occasions.

Why can't the people in charge make sure that the bus contains the bus number on the inside? It is an essential piece of information.

Maybe they want to change the bus to another service, when needed. In that case, they can have a moveable display.

Can someone who is living in another city help me to check if the bus number is displayed inside the bus? Thank you.

Welcome to Singapore. It is run by idiots from the PM down.