Speaking as a former motorcyclist, I think it means that you are FAR more likely to get killed through no fault of your own on the way to the airport
And that is really the big difference. On the road, a large % of accidents are caused by someone else. In the air, the % is absolutely miniscule.
I think taxiing is far more risky than flying. One might not get injured but it enough hurts the chequebook. A bit of carelessness on the ground can easily end one's flying for good - a few £20k bills and nobody will insure you.