Third refuel on the Prius today.
I thought I was very low on fuel, so I opted for a Texaco station at the bottom of a hill, but it turned out that I wasn't low at all... I have to learn to interpret the meter (it nags).
After having traveled 896 kilometres on this fuel tank, I added 42.30 liters (the price per litre was 1.285 euros), yielding:
4.72 liters per 100km (Prius meter shows 4.8, on the edge of 4.7, it was jumping from 4.8 to 4.7 in the past few days).
Converted to other measurements, this means:
49.83 MPG USA
59.85 MPG Imperial
Referring to Tweaker's request, I took some pictures of the Prius fuel efficiency, braking regeneration, and engine selection screens with my phone camera while in traffic jams, and with my mom's digital camera while standing still, but they are all bad (phone cam sucks, mom's camera always flashes inside the car, didn't find how to turn flash off). I will try again with another camera in the coming days and edit this post when I get a few suitable shots).
I conclude that driving fast uphill helps fuel efficiency a bit, especially when the road thereafter is flat or downhill.
Solar Hydro
P.S. My next experiment (perhaps I'll start tomorrow) will be to inflate the tyres to 42psi front and 40 psi rear. Supposedly this yields better MPG. I'll have to drive slowly to a petrol station nearby to avoid heating the tyres before the air pump. I didn't adjust the tyres on refuel tonight because they only had an analogue bar meter, and I didn't know the psi/bar conversion from the top of my head ;-) Perhaps I should also try this...
http://www.treehugger.com/files/2005/10/inflate_your_ti.php
P.S.2. This time the consumption meter reset itself on its own at the petrol station, just when I was planning to leave it running indefinitely to know my overall efficiency. I need to investigate that.
P.S.3. I wish I had known that I had quite a bit of fuel left, because actually I was planning to re-try the Total Excellium fuel that the car was filled with on purchase. Total claims that this fuel is more efficient (i.e. you consume less), and fact is that my first tank was by far the best of the 4 tanks I have now used overall. That was also the tank with which I drove in the mountains near Francorchamps, which makes me consider that Total's claims might have merits, even though I remain very very sceptical. Note that all Belgian petrol stations serve 95 octane and 98 octane (I always took 95 - which is the standard quality) whilst apparently the Prius runs fine on the American 87 octane and any ethanol mixes.