Try to look at the meter...there is a red light number on screen showing 1, or 0 or..any number. That's determining how much riyals/km rate are you being charged.

If going outside of Doha he may put the number as 0...(I'm not really sure..but as an example), if in Doha the number is showing 1.

There was one time a good hearted Karwa driver told me about this and even showed me the rate schedule (kept in glove box). He also advised me so next time I won't be cheated by other drivers. It's really helpful!

So next time, you should get this ionformation from the taxi driver too!