Hi everyone,
I have my IS300h Business Edition since January this year, and have done 15500 miles (25000 km) up to now.
My total average since January is 42MPG (6.7 l/100km) calculated, being 65% highway, 25% regular roads and 10% city. Although I have to mention that it has gotten way better after 6200 miles (10000 km)
Mostly I drive in Eco mode, with some sports mode in between - do not understand what the normal mode is for, either you want a sporty car, or you want to save fuel.
On the one route I do regularly (about once a month) which is 560 miles (900km):
60 miles (100 km) roads passing trucks in sports mode @ ~65mph (105 km/h)
125 miles(200 km) highway at 95 mph (155 km/h) (cruise on)
25 miles (40 km) highway at 110 mph (180 km/h)(cruise on)
350 miles (560 km) highway at 90 mph (145 km/h) (cruise on)
Mostly drive ECO on that route, besides some sport mode for passing trucks on the regular roads. I get an average of 44.8MPG (6.3 l/100km) (calculated).
Most I have gotten into my tank is 67 liters and 691 miles - this was only when I had 10 liters reserve in my trunk, just in case.
If I tank 98 Octane, I get a slightly better number: 48.7MPG (5.8 l/100km), and with 10% Ethanol in the fuel slightly worse,41.5MPG (6.8 l/100km)
Hope it helps to compare!
I converted from l/100km to MPG using the imperial system, hope that the right one!