Can I just use a collar or do I need a harness?
Harness. A harness will be much safer for your pet in the event of an accident.

Am I legally required to use a Booster Seat for my Dog?
In some states, yes. Check with your local government first, as some may only stipulate the use of restraints. Keep in mind that the law that pertains to dog booster seats could legally be open to interpretation.

How will I know if I can Use a Booster Seat on the Passenger Side?
Again, it’s best that you check what the law says from an official source. Remember to move the car’s chair back some distance, which prevents injury if an airbag is actuated during an accident.