If faced with the choice, would you rather buy a hybrid vehicle which runs on gasoline and electricity and gives good city mileage and burns fuel more effectively while emitting way less CO2 and other pollutants. Alternatively, would you opt for a diesel vehicle, which will give you more mileage than a hybrid but diesel cost more than gasoline on one hand but you use less of it and with improvements made to these advanced diesel engines most of these engine run on biodiesel (combination of vegetable oil and animal fat), hence the greasy spoon odour from the exhaust. Both are good options, but the fact remains that until diesel is not refined so that the sulphur level is lowered significantly, diesel obtained from fossil fuel poses too much of a hazard. That being said, at one point Krissy and I had considered the Volkswagon Jetta but for some odd reason we did not look into it too closely, something we may regret in the days to come with the prices of gas currently between $2.79 – $2.89 per gallon in and around Ann Arbor, MI. My Mazda (15 gallon tank) is currently giving us 27 mpg combined. The Jetta (14.5 gallon tank) gives approx. 38 mpg combined. So for about a dollar or so more, if I had a Jetta we would get about 146 miles more out of diesel. Downside, over the course of a year the Jetta would emit 6,528lbs of CO2, 60lbs of CO, 45lbs of NO, 1,842 grams of soot or particulate matter and 22lbs of smog. I used the gas mileage calculator on the Hybrid cars website to get the emission infomation.