A good idea unless it becomes popular.

I'm picturing bumper-to-bumper traffic on a highway with a cloud of drones overhead. Each person in their individual car using their individual drone to all report back the same thing: that everything is moving slowly because there are just too many cars on the road right now. With luck, the drones only crash into each other every once in a while, just like the cars below.

Just get cb radio

There was a recent story about a medivac helicopter not being able to land to help accident victims because someone had parked their drone over the wreck to check it out/get clicks.

Mobile maps apps already do this pretty well.

Launch while parking with an unfamiliar trailer or in an unfamiliar area.

This may not be legal, per the FAA.