As my experience goes, it's not unusual to have the same sort of auto accident a certain number of times in a short time period. Several years ago I was hit three times within a month--when my car was parked! About five years ago I was hit three times during the Christmas season--all of them by people backing out of parking places at stores.
And then there were a few periods, better forgotten, when I did the hitting--three times within a couple of months.
My automobile luck seems to work by the Rule of Three. Since Husband's vehicles have been rear-ended twice this week, let's hope his luck works by the Rule of Two.
Ooops! Late-breaking news: Husband's rental car was scraped on the side earlier in the day, which fulfills the Rule of Three. He's in the clear from now on.