First injury is more likely in residential areas. Tapping a car is less of an issue than tapping a pedestrian which are harder to detect and predict.

Second while the number is still a low enough number not to be particularly relevant other than to say the gross order of magnitude. However...

Google's autonomous vehicles have crashed 36 times in the Mountain View area

https://www.businessinsider.com/cruise-waymo-apple-which-sel...

Waymo spokesperson called the research "deeply flawed" and said it "reflects a poor understanding of the data as it fails to distinguish between a vehicle that drives hundreds of miles per day on public roads, with one that seldom leaves its garage."

In other words they don’t disagree with the number of crashes, even when excluding other areas.