The Great Gatsby, and not even trying

I'd like to know why a character repeats "and not even trying" in this excerpt from the chapter Three of The Great; does the phrase mean just that he was not attempting to drive at night or that he was not making the least effort to be a good driver at night?

“Well, if you’re a poor driver you oughtn’t to try driving at night.”

“But I wasn’t even trying,” he explained indignantly. “I wasn’t even trying.”

An awed hush fell upon the bystanders.

“Do you want to commit suicide?”

“You’re lucky it was just a wheel! A bad driver and not even trying!”

“You don’t understand,” explained the criminal. “I wasn’t driving. There’s another man in the car.”

Thank you.