I believe if you drive a 2.0L car in traffic jam, definitely you do not expect it to save fuel. Especially jam like yesterday where people queue up to pump petrol till making the traffic halt to a standstill.

I drive a 1.8L C segment car too. If jam till cannot move , fc meter will drop to 7KM/L . Especially when I trying very hard to keep up with the car in front to reduce gap to minimum to avoid ppl from cutting queue.

The mazda 6 is using 19 inch rim. So you do not expect to save fuel too. 20.7L/100 KM I believe is due to customer full throttle with short distance to test the power of the car.

If want fuel saving , of coz you go get a Prius or an Axia, Mirage , Attrage .

~my 2 cents~