There are a lot of known health issues with commuting by bike. Never mind the risk of crashes/accidents. Saddle sores. Hand issues such as chafing, callouses and carpal tunnel. Sore leg muscles, both during and after. Back issues. And the big risk, enlarged heart. (Also heart rate and blood pressure can get scary low. Not an issue driving.) I get reminded of my enlarged heart every time i get chest X-rays or a new doc for my physicals. Compare this to driving. No sores. No exertion straining the back. Heart stays small.
I have some idea what I am talking about, I've done roughly 200,000 miles each, driving and riding and roughly half that has been commuting or city riding/driving. (And biggest health issue of bicycle commuting? Save ER visits, we support the national health establishments poorly.)