Engineering goals are typically rooted in addressing the functional needs of a product. While these engineering goals and specifications can be important in consumers' buying decisions, many times the first impression of the product comes from judgments of the product's aesthetic form. For this reason, this paper set out to study how well human judgment of performance based on a car's shape correlates with the actual measured performance of the car's shape, and what features of the car's shape most influence this judgment. More specifically, participants were asked to rate how aerodynamic, sporty, fuel efficient, and rugged a computer generated car design appeared to them, and these ratings were analyzed against the actual aerodynamics of the vehicle as well as key indicators of sportiness and cornering stability such as center of gravity and wheel stance. The inter-rater consistency of human judgments was also studied. Using this human judgment data, the attributes in car design with the greatest effect on participant judgment of vehicle performance were identified, and were compared against their importance and effect in actual vehicle performance. Analysis of this data gives key insights about how car designers can create designs that better convey the desired goals of a car to consumers while also meeting those performance goals. The results of this study provide evidence that consumers are reasonably accurate at determining certain functional performance traits, such as aerodynamics, but are insensitive to other traits, such as the wheelbase of the vehicle design. It was also determined that the stylistic and functional performance judgments of the consumers surveyed may have been influenced by social norms and conventions learned from past experiences with vehicle designs.