If your Puggle rides around in the car without a safety restraint, they'd be in serious trouble even in a minor car accident. I recommend buying a safety harness for your Puggle to wear in the car. They're not that expensive and they'll save your Puggle's life in the event of a wreck.
My Puggle wears one and she loves it. It has a soft cotton interior, so it's more like a warm coat than a harness. It also keeps her from jumping out the window and running around, which she actually did on a couple occasions. Don't wait for something to go wrong... Be proactive about protecting your Puggle!
