Friends don't let friends ride in the back of open pickups. Every time I see a loose dog in the back of an open pickup truck I see an accident waiting to happen. I'm reminded again of how dangerous this is and how few owners realize it.
Dogs that are riding in the back of open pickup trucks may look like they're having fun with noses testing the wind and ears flopping. They seem to be enjoying the trip but they are not safe! Eye and ear injuries are common from windblown dirt and debris. There is no way for them to hold on if there is a sudden stop or rapid change in direction. There is nothing to keep them from flying from the truck bed and hitting the pavement.
Even with a restraint it is not safe for your dog and there is no harness that is proven safe in this situation. In fact, there have been cases where the dogs restrained by leashes have been strangled or dragged after being thrown from the truck bed. The safest way for a dog to travel in an open bed is inside a sturdy pet carrier that is securely attached to the floor or side of the truck so it cannot slide around. Crates such as those used by the airlines work well .
As the wife of a veterinarian, I have seen firsthand the tragedy and horrific injuries dogs suffer after jumping or being thrown from the back of an open pickup. Skin is peeled off with abrasions sometimes as deep as the bone. Bones aren't just broken but shattered, causing severe damage to muscles and surrounding tissue. Extensive surgery and physical therapy is required to return to function.
It has been estimated that 100,000 dogs die each year when tossed from the back of open pickup trucks. Muddy upholstery is a small price to pay to keep our companions safe when we travel.