As a former ICU nurse I can tell you that someone who has been taking good care of their body, is fit and healthy, has a better chance of survival and less complications while recovering as someone who didn’t. No matter the injury.
If you get hit by a bus and your lung is compromised it has a harder time compensating for the injury if it was already damaged.
So yes. You might have a better chance to survive a car crash if you haven’t been smoking.