1) Get your dog comfortable with being in an automobile.
Simple trips down the road and around your local neighborhood are a good idea before you take any drives that are long-distance. You want to find out how your dog reacts and you also want to find the best method for getting your dog strapped in your vehicle.
2) Be very careful allowing your dog to hang out the window.
Many people do not realize that a dog could get an eye injury that can be really brutal with its head out the window. Bugs and other debris could possibly fly into your dogs eye and cause great damage.
3) Safety barriers.
If you have an SUV or vehicle with a wide trunk area, you may think about getting a safety net, dog barrier or gate. This is good for larger dogs that will not fit safely on the seat of your automobile. An alternative is to have your dog in a safety harness strapped into the middle seat. Multiple dogs should be held on separate buckles, via harness systems.
4) Proper Identification.
This is one of the most important things you can ever do and is a vital part of traveling with your dog. Make sure that you have proper identification for your dog! In case of an accident in which your dog flees, your dog will at least have the necessary contact information on its dog tag. And in the case of emergencies, having extra copies of vital veterinary documents like shot records will be extremely important.