Food for thought:
https://www.outsideonline.com/2326736/we-need-talk-about-keeping-dogs-safe-cars?utm_medium=email&utm_campaign=Indefinitely-Wild-07172018&utm_content=Indefinitely-Wild-07172018+Version+A+CID_2ce12ffe2004faaac6800f5b1366314e&utm_source=campaignmonitor%20outsidemagazine&utm_term=READ%20MORE

Definitely a must have. I don't like making my dogs ride in the back seat, but if I'm taking all four, or my husband is traveling with us, then that's a must do for them. At least in the front seat, they have an airbag if we were in an accident, and, they are always harnessed in to prevent them distracting or causing me a problem while I'm driving.

I wouldn't ask them to ride in the hatchback portion of my SUV and, of course the king cab pickup has only the front and back seats because no way would my dogs ride in the bed of a pickup.

It's illegal in Oregon for a dog to be unsecured in the bed of a pickup. Of course some people claim that such a law is a further example of a cultural divide between rural and urban parts of the state. Me, I'd rather have a live dog.

Have been curious about the harnesses.  I always thought crates would be the best option.  A harness with one attachment point seems like the dog would get whipped/ swung around.  The approved harnesses seem to have solved this by having the seatbelt run through two straps of the harness v.s. the ruffwear which has one loop for the belt to run through, and, of course, is not on the approved list.

Would like to see the tests run with seat material that has a more realistic padding (or lack thereof) than the padding on the test sleds.

I got the Kurgo harness when we went down to TX, mostly because we were going to be in a crew cab truck and not my Explorer. The whole purpose was to make sure that the dogs couldn't bail out of the truck at a gas station since there were so many of them in a small space. For the most part though I have always let mine run loose in the Explorer. I did see with the crew cab truck what this article mentioned where even with the harness if we were going to have to brake hard they were going to eat seat before that harness would ever stop them. If I could secure the attachments for the harnesses dead center of the open cabin of my Ex then they might would have enough space around them to not hit something before the harness caught them, but that's still assuming you aren't in a rolling situation. In a rolling, skidding, situation I would expect to see what you mentioned, Mike, where they will just sling around and bounce off everything. A good crate that is locked down to the floor of the vehicle would still be my go-to if a person has the space and is truly worried about safety. While a dog traveling from the back of a truck to the front of the truck may have momentum enough to be 2700+ pounds of force. Traveling from the front of a crate to the back of a crate is going to be a lot less force. I've seen wrecks where we've had to catch dogs that got loose from inside the car. I've seen wrecks with bird dogs in the back of the truck in boxes. The boxes in the back usually always make for a better off dog. Some of those bird dogs faired the accident far better than their owner who was strapped in in the front seat with that air bag.

I will not put my dog in the front seat of a vehicle with a passenger side airbag. It can kill them and frankly children or really short people faster than the wreck can.

https://www.dmv.org/how-to-guides/pet-travelling.php

https://www.alldogsgym.com/miscellaneous/articles/miscellaneous/nh-sunday-news-dog-tracks-column-sp-1405673179

Also, if the animal is under 80 pounds they often won't activate a passenger seat airbag so the bag won't deploy and the dog will go through the windshield if it doesn't have a secondary restraint.

It seems one has to make a choice between every day convenience, dog comfort and safety.  Not liking the options.

I do use the kurgo with the stainless steel buckles - convenient, goes on easily, does keep the dog from roaming around but I do worry about failure in a significant accident. I don't like the videos showing the rebound/flip onto their head that the crash tests show.

I don't like any car harness I've seen tested. As the article points out, none work in an accident for large breeds.

The only one that makes me happy is the Kurgo when used IN THE BUNK of a sleeper cab semi. Those bunks have bunk straps - required if someone is sleeping while the truck is in motion as with team drivers. You can strap the dog in in such a way that he can sit or lay down and, if there is a sudden stop or accident, short of a roll over, the only place the dog bounces is on the bunk mattress with a goof 12 inches to spare before falling off forward, a couple of feet on either side and, a padded back wall.

Unfortunately, they don't build passenger cars with the idea of a person laying down and sleeping in the back seat. If they did, we'd have better dog safety options. We can't all drive semi trucks. I'm just glad that's my transportation for overnight or longer trips unless I'm flying.

Bev - we have a 4Runner and I put the back seats down, use the cargo tie downs as well as the latch points for the seat backs to attach my guys kurgo harness. Still, I worry about my big boy.

I understand that. In a 4 Runner, I'd get one of the big cargo air bags, called dunnage bags to put against the back of the front seats. Depending on size, they run from 15 to 200 USD and, are reusable, as in one big one or, two smaller ones would last a lifetime for that use.

At least that would provide giant pillows for the dogs if they were thrown forward in an accident or sudden stop. They are medium weight vinyl and, are washable with warm water and dish soap.