That's not really a fair comparison because you can only accumulate car crash risk when you're commuting, but you're accumulating cancer risk for every moment you're alive.
Pedestrians are killed by cars, quite often. They are 1 out of every 6 vehicle fatalities. There's also per-trip associated risk which is separate from per-mile risk.
OK, but when I walk to the nursery every morning, we can take the quick route down the big road with traffic jams, or I can go 5-10 minutes out of our way on roads with no traffic and through a park.
Similarly, every time I'm out walking I try and not walk on the large roads with lots of traffic, it all adds up.
If you live long enough, everyone will get cancer. Lots of people abuse their hearts enough that they die from that first but some disease get more and more prominent as you age. These are the reasons that we don't recommend testing for colon cancer at age 15 for most people.
Eventually we all have to die of something. Evolution does a great job optimizing for protecting us against ailments that kill us before breeding age, but a pretty crap job of keeping us safe from things that kill us in old age.
Cancer is a major cause of death as we age because it gets more likely the older you get. You can certainly take steps to avoid making yourself extraordinarily vulnerable (don't hang out around tons of radiation, wear sunblock, don't smoke, etc) but enjoying the smell of a new car seems unlikely to be the factor that suddenly means you will die of cancer.
You can remove your risk of dying in a car crash simply by staying at home, away from roads.
You can't remove your risk of cancer.
If you were enclosed in a windowless box with sufficient food, water, and air to live then it would be a race to see which would kill you first: boredom or cancer.
Chance of dying in a car crash, 1 in 77. https://www.cars.com/articles/are-the-odds-ever-in-your-favo...
Chance of dying from cancer, 1 in 5. https://www.cancer.org/cancer/cancer-basics/lifetime-probabi...