Originally Posted by teoman
I know in traffic nothing much can be done for fuel economy besides getting a smaller car. But i do frequently go on longer trips. For daily commute i try to use my motorbike as much as possible.
If it helps at all, the gasoline version of your car is EPA rated for 14 mpg city, 17 mpg highway.
Actually, in traffic and city driving is where you can get the most significant improvement in fuel economy. Look ahead as far as you can to anticipate traffic conditions ahead, try to look through windows or around the car in front of you. You know, the usual stuff. Check out the 100+ hypermiling tips at the top of the page and see what techniques you can use.
Remove any unnecessary weight, like unused seats, or misc junk. I don't risk removing my spare, but I also don't have an inflater/plug kit to patch a tire. Only you can decide what you are comfortable with. Pump the tires up more, try to maintain the correct pressure bias if there is one. For example, my accord specifies 32 PSI front, 29 PSI rear, so I set it to 51 front, and 47 rear.
Regarding your water spraying idea, that is actually a really cool idea. Make sure you monitor your engine temperature with those grill blocks, the idiot gauge is not a suitable replacement.
I had an idea for what you could do to optimize the water sprayer. Place a large water tank in the front of the car and connect a thin rubber hose above the grill block opening. You could either drill really small holes all around the hose, or you could use drip irrigation hoses. Also, install a closeable valve before the hose so you can turn the water supply on before a trip, and off when you are done. With this setup, you wouldn't need a pump and the associated electrical draw.
If you are going to do this, consider using distilled water in the water supply, less chance of things rusting.
Another idea I just had: Position the tank at about the same level, or lower than the supply hose. Have the end of the hose open and hanging in the wind. As you increase speed, the air flowing by may suck the water up the tube, supplying more water at higher speeds. I made a diagram of what I am explaining.