Every mile of you driving causes a non-zero amount of risk of injury to other road users. The specific crash might be "accidental", but by driving you're making a conscious choice to cause harm to other people.
Maybe a better example is to refer to the marginal effects on mortality caused by vehicle pollution, whereby simply by driving the vehicle causes harm to others, without necessitating a direct consequence of the behavior itself (such in the case of a crash). If say, one in every 10,000 trips resulted in a crash, it would be a bit absurd to say each trip I drive results in 1/10000 of a crash, whereas emitted pollutants is discrete and measurable.