People in China and India who can afford cars are perfectly literate. In fact as per DKaz most of the people who can't are perfectly literate as well.
People understand well enough that for example less deflection is better. Its just a number, and to that other guy all you have to do is standardize the test that collects this number and the arbitrariness of the rating will disappear. Its a different thing.
The star rating itself remains entirely arbitrary. It boggles my mind that you don't see this. You say its based on some statistical distribution of probability of injury or death. Well if so, and my car is rated 4 star, can you tell me how likely I am to die in a head on 30kmh crash with a concrete wall? Give me a percentage. Translate that star for me.
I mean, even if we ignore the fact that stars are awarded and taken away for the presence or absence of specific features like airbags and esp, why do we bother with the stupid stars at all? If it really is based on some probability distribution then why not just quote the mean of that distribution? Surely even the barely literate can understand a percentage.
And for the literate, a standard deviation too please.
If you can read a newspaper, you're literate. That could mean you have a phd in molecular biology, or you could barely figure out what you're reading.
NCAP ratings, NHTSA, IIHS all have simple ratings systems for a reason, to allow the largest number of people to understand the relative safety of a car to it's peers.
Fuel economy is simple, you get two numbers, highway and city. How many numbers would it take to adequately tell me how a car behaves in a frontal collision, frontal offset collision, T-bone driver's side, T-bone, passenger's side, rollover, rear-end, and offset rear-end? Who would even bother to pay attention to them?
The west never cared about safety ratings either until they became widely used and they became burdened with the costs of the injuries and deaths autos cause.
China and India will eventually get to that point too, but right now they have bigger issues to deal with.