Consider this, most station wagons rear cargo area is a crumple zone. Somwhere in the passenger area is best inside of a crate even better. If in the front passenger seat, turn off the airbag.

I don't know if this is actually safe or not, but I have 2 large dogs & I drive an Avalanche. They go every Sunday w/ me to my parents house to play w/ their dog. Anyway, the Avalanche has the fold down seat that opens up into the covered bed of the truck & that is where my dogs lay (where the back seat is). They are usually pretty hyper when they first get in, but they calm down & lay there until we get to "grandma's"... then, it's a whole different story! :) Anyway, w/ this arrangement, I feel like my dogs are as safe as I can possible get them w/o crates. The front seats & the covered bed are on both sides of them to protect them, and the heighth of the front seats would definitly keep them from flying into the front w/ me. But, they are not buckled in in anyway, I'm not sure I could even do that w/ my St. Bernard since I don't know if he could comfortably/safely sit on the seat.

Consider this, most station wagons rear cargo area is a crumple zone. Somwhere in the passenger area is best inside of a crate even better.
I have a big, giant doberman/coonhound mix. I drive a smallish wagon and used to crate my dog in the cargo area. Until a friend told me this same thing QQ posted.

Now, I strap him into the back [passenger] seat using one of those dog-seat belt attachments. (see link) It took a while for him to deal with being strapped in. I started out by driving him just a few miles and increased distance/time until he was cool with the concept of being restrained. I think this seat belt idea is much safer than a crate in the cargo area.

Here is a link that might be useful: Restraining Device Link

The nice thing about those is if you slam on your brakes the dog doesn't go flying, which they can do inside of a crate to some extent. The seatbelt harness tightens when the seatbelt tightens which of course happens when you slam on brakes.

Riley is 11 pounds and I used to strap him into a travel crate in the back seat. However, he would get car sick every time. So I purchased a basket that straps to the front passenger seat and has a harness attachment to keep him secure. This way he can see out the window and he doesn't get car sick and he can either lay down in the basket or sit up - he usually likes sitting up. I've slammed on the brakes a couple of times when he's been in it without a problem.

Also keep in mind that if you were to be invlovled in a serious accident and your dog is not properly restrained they become a danger to everyone in the car via their body being tossed about.

It is safest for both you and your pet to be restrained. Seat belts save lives, no one denies this, so why wouldn't you use one on your pet?

In most vehicles you are unable to turn off the passenger air bag. If the air bag cannot be turned on/off then it is never safe to have your pet in the front passenger seat.

We use the seatbelt restraints... works fine for us.

I have 3 dogs, a Chocolate Lab, and two Olde English Bulldogges.

When we go to camp we use two cars and I take the bullies. I have a Pontiac Vibe and use a hammock in the backseat, I think mine is made by Outward Hound. I also have two small black straps that have a seat belt buckle on one end and a collar clip on the other. You can adjust the length, but I keep them short so the dogs cannot get up and run around. Bullies are sleepers anyway, so by the time they wake up we're there.

The lab rides in the other car, which is a Toyota FJ Cruiser. She just sleeps on the back seat.