This is a cute take on the challenge. It does meet the Beatles song lyrics/title requirement, but I think it's downfall in voting was probably the fact that it looks more like a vacation snapshot than a planned image for submission in a contest. The composition is a bit too centered. Perhaps cropping on the left and getting in a bit closer would help. It also appears that they are just walking by the car and not actually attempting to drive it, so that might have played on your score a bit. However, 5.6 is nothing to sneeze at. I'd take it and run. ;)
Keep shooting and let me know if you have any questions. :)
Nice shot, but fitting it to the title is hard for me. I don't get any feeling of a connection between the people and the car, nor the people to themselves for that matter.