Might not be the biggest risk to your life but it’s 2.3% out of 55 Millions death (so, just to put things into perspective, we’re talking 1.6M deaths per year).

Besides, the risk is not only death directly in an accident. For those 33% who died from heart diseases: stress is a risk factor for cardiovascular disease and the paper does mention specifically work stress as a risk factor

The risk of a cardiovascular event was higher in patients with a history of social isolation (OR, 2.47), marital stress (OR, 2.28), work stress (OR, 3.2), childhood abuse (OR, 2.78), or trauma (OR, 2.67).

Again not all of it will be due to commuting to work, but raising your stress levels by having you commute needlessly in traffic is not good for your health.