Apparently, wieners and other small dogs require special attention:
Ms. Selter, whose organization collects and analyzes pet safety data, said that even when safety restraints were used, they were often used incorrectly.
She recommended that most dogs be secured in harnesses that strapped across their chests and attached to car seat belts, like the PetBuckle harness, which clips onto dogs and into seat belts. For pets that need to move a little bit, there are tethers — like the Bamboo Quick Control Leash, which comes with a seat belt latch — that attaches to the harness and clips onto the car seat belt.
Harnesses are not for really small dogs, Ms. Selter warned. “Wiener dogs should not be in a harness,” she said. “If he falls off the seat, it will snap his back.”
Pet safety advocates also warn that dogs should never be tethered to seat belts by their collars. “If you hook the tether to the pet’s collar, if you have to stop suddenly, you could injure the pet’s neck,” said Thomas James, president of PetTravelCenter.com, a Web site for people who want to take their pets on vacations.
Update: Here’s more on the issue of Dachshunds in cars.