That's why it's important to regularize drone traffic before it get out of hand. Safe flyways to get to neighborhoods. Delivery routes that find residential homes less busy (e.g. when school is in session).

On the subject of vehicles-causing-accidents, it's possible delivery trucks trying to beat a deadline may be over-represented in statistics. Speeding, driving aggressively, parking all over the place. So there's that.

Drones are point to point delivery, which is why they're currently used for transporting high priority items like cooked food and blood transfusions. If drones were legalized in more places, they'd substitute for quick trips to the store. This would be safer for everyone involved and reduce pollution.

Planes fly at much higher altitudes than delivery drones, so the only collision worries would be near airports. The FAA already bans drones near airports and requires special authorization to fly a drone within miles of major airports. Even if you get approval, you can't exceed 400 feet above ground level.