People love their dogs, right? So they shouldn't give them access to completely open car windows in moving vehicles. I have been seeing so many dogs with their SHOULDERS out the passenger window--on the FREEWAY! I am going to have a heart attack, I swear. I was walking Tommy on a major street today and was rather hoping the fluffy yellow retriever mix would take advantage of being parked at a traffic light and make the plunge to visit Tommy and me. Perhaps his person would have learned a huge lesson--one a previous neighbor learned the hard way when her maltese mix jumped out and was run down. Awful. Preventable. Stupid.
The intelligence of dogs has been compared to that of a two- or three-year-old human; you wouldn't trust a toddler to know enough not to jump out. Did you know that dogs suffer eye injuries from debris? No heads out windows, please.
Don't forget about the force of your passenger airbag. Fluffy should ride in the backseat where it's safer--and less of a distraction. And if you are in an accident, your dog, esp. a small dog, becomes a projectile. Tethering is essential. Use a crate or a dog seatbelt or a doggie booster chair or even just slam the end of the leash in the car door so the dog doesn't hop from the back to front seat while you're trying to focus on driving. Easy breezy.
And while we're at it: if your dog doesn't enjoy the car, it's time to make it nicer. Build gradually on getting the dog used to the car (starting by just sitting in the vehicle and not moving). Treats can improve many scary things!
We have to protect our fur friends; we're all they have.