Re: Software, mileage, and urea
The EPA mileage test, while not quite "real world", does deliver a vastly different picture of vehicle efficiency than the EU test does. It's close enough that a careful driver can beat the claimed figures, at least.
That being said, neither of the tests are supposed to reflect reality. They're simply meant to be a comparison between models. The EU tests might be wildly out sync with reality, but assuming all manufacturers game it the same way then you can compare different cars with each other.