Factual error: Rocky buys and drives a Trans Am. Later, we find out that he can't read after his commercial goes horribly wrong. He couldn't have a driver's license because he would need to pass the written test first. You can't take the test if you can't read the questions or the driver's manual for that matter.
Suggested correction: It's not that he can't read at all, he just reads slow and has some trouble. It may or may not be enough to hamper him from taking the test. But is it ever established that he has a driver's license? He wouldn't be the first person in Philadelphia to drive without a license.
When you can't tell the difference between simple words like rat and cat, there's a pretty good chance you can't pass a written driver's test, which is why I said he "couldn't" have a license.