The better comparison is probably significant injury per city mile. Accidents on highways are way less common (both per mile and per hour) than city since there

The better comparison is probably significant injury per city mile. Accidents on highways are way less common (both per mile and per hour) than city since there are way fewer points of interaction on highways (although occupant deaths are more likely on highways since speed is higher). Unfortunately, I'm not finding good breakdowns for car crashes based on road type.