Well.....I chickened out when the last bar went off and drove 2 miles to the gas station.
Here's some numbers for gas tank calculations or PZEV civics that I've figured out so far:
tank capacity according to manual: 11.9 us gallons.
I've had my car for 4 months and so far filling up when I got to 2 bars was:
10.4, 10.15, 10.09, & 9.95- leaving at least 1.5 gallons to use (keeping .4 gallons in reserve for my sanity)
therefore, divided equally- last 2 bars are .75 gallon each, right?
So I had gone 593 miles when the last bar went off. Of course I had reset the tank meter by accident, and didn't know I was quite that close- I thought I had about another 15 to go. So I bought gas and the fillup was 10.56 (to automatic shutoff).
that leaves approximately another whole gallon in the tank when the last bar goes off.
I don't know how definite that is, since it's based on computer calculations of fuel consumption and mileage.
I also cheated a little- I very carefully measured .5 gallon gas at home the day before and added it to my tank- I was concerned about running out and damaging the catalytic converter etc. (not to mention the walk from where-ever; I have run out of gas before and had to walk).
so totals for the trip were: 11.06 gallons/595 miles/53.79 mpg
which is still my highest tank average so far, so I'm happy. next time I'll definitely beat the 600. Hey- give me a break! I'm a newbie!