The merits of a website aptly named "Pickuptruck.com" testing a vehicle such as the Smart Fortwo are, shall we say, debatable. What's not, however, is how cool it is that said website drudged up the good ol' Bambi vs. Godzilla cartoons for their title of the "comparison test". Do you remember going to see a movie in the 80's and watching Bambi get stomped? Good times, good times...
I am not going to write anything bad about the Cummins Diesel engine. I think it is a fine engine, and well worth it for the people who need it's amazing towing and hauling abilities. However, to have that truck as your primary, or worse, only transportation option is probably not a good choice. I thought that some of their math was interesting, including the emissions per pound and mileage per pound, but I'm not sure we have an apples to apples comparison there, either. I would argue that the weight of the safety equipment versus overall vehicle weight would skew the results in the Ram's favor in that type of test. To put that another way, how much mass (steel, aluminum etc) is required to make the Smart safe in an accident versus a vehicle such as the Ram?
Bottom line time: Both vehicles have their purposes, and both are fine choices for their intended roles. Taken for what it is, this comparison is a fun read, if you've got a few minutes to spare.