Hey,
I got a hammock. I'd rather use the cargo area for groceries and crap I always seem to have, also dog (40lbs) likes to sit and stick nose out window/be closer. I'm also planning on some long road trips with a friend and dog(s), so want to put travel stuff in the way back out of sight / under the rear cargo cover.
I live in Seattle so I walk the dog in the park mud almost daily in the winter (also hike so more mud/dirt), and take her (and a friend and her dog) in the car daily. Because of the hills here, without the hammock, the dog(s) would slide right off the back seat onto the floor whenever I slowdown/stop on a down hill. I also occasionally dog-sit a 70lb dog who sheds a ton, so really want that one in the hammock and secured. The hammock I got also allows a 3rd passenger be in the back seat with dog(s) and hammock.
One of the downsides of hammocks I didn't think about is you need to leave the rear headrests in place to support them (some folks like to take the headrests out when not in use for better rear visibility). I got this one (
https://www.amazon.com (commissions earned)) because of the zippers and associated flexibility, but I would recommend any well rated hammock. So now my 40lb dog can be both in the hammock AND be buckled in (I got this seat belt clip:
https://www.amazon.com (commissions earned)) AND still feel like she is part of the action if I zip open the middle zipper so she can see us while laying down.
Back story: I had a RX-8 since 2004 and my dog fit perfectly in the rear-bucket seats and did not slide around, and was easy to clean up afterwards (just tucked some thin camping towels over the rear seats). But I had to get a new car when my RX-8 was totaled, which was a wake-up call. An oncoming driver was "blinded by the sun", didn't see me, and turned left in front of me. I could not stop and hit the car broadside. My dog was in the back and fortunately barely moved as she was curled up in the bucket seat.
So...enter my two week old 2016 CX-5 as a replacement. (1) No bucket seats, so she would slide around, and (2) perforated leather from which it seems like mud and dirt would be a pain to clean out. So... enter hammock and seat belt clip. As my dog now wears a harness (
https://www.amazon.com (commissions earned)) as I occasionally need to carry her, I leave the seat belt clip in the car and just attach it to her harness to keep her a little more secure (she can still sit up and look out the window). I don't always use the belt clip around town, the hammock obviously keeps her from sliding off onto the floor, but for longer trips / highway driving... Comment: Attaching the seat belt clip to a collar (as they show in the pictures on Amazon) just seems like a recipe for disaster if in an accident.
Sounds like you are putting the dog in the cargo area - just consider making sure he/she is secured back there - can never account for other drivers!
Best!
PS - I threw down a doggie blanket on the hammock as the hammock surface is a bit slick.
PPS - For you folks who want to bring your dog(s) everywhere and leave them in the car, I just ordered these so I could leave the windows wide open but still have the car fairly secure:
http://www.muttmanagers.com/. I'll post a review when I get them.