What is the best four seat car for carbon impact?

Question

Trying to purchase new vehicle for family use. Want to get best mileage - but more importantly best overall carbon impact. Which specific vehicle? Willing to get Hybrid, Biodiesel, etc.

Answer 1

Why just carbon? There are other emissions to also be concerned about.

Take a look at http://www.epa.gov/greenvehicle
There you'll find vehicles listed by their emissions and then their fuel economy, sorted out by vehicle type (small/medium/large car, station wagon, minivan, small/large SUV, pickup truck, etc.). (fuel economy is directly proportional to CO2 emissions)

If all you care about is CO2/fuel economy, then you can use http://www.fueleconomy.gov/ to find the best cars.
or:
in the UK: http://www.vcacarfueldata.org.uk/search/fuelConSearch.asp
in Canada: http://oee.nrcan.gc.ca/transportation/personal-vehicles-initiative.cfm

Answer 2

You want to buy a four- seat car for family use. In USA you can choose whatever car you wan (The cc of the engine). but take from me, buy a car that has a motor of (1600-1800cc) not more than this. Don't think about the biodiesel because its maintenance is expensive. Take it from me and buy a VW car, or Ford.