John Van Zante does it every year. He sits in closed car left in the sun to show how quickly it can become potentially deadly.
He says people don't realize just how fast the temperature can rise.
"Who does this? People who don't understand that you can take a vehicle that's 80 degrees and have it raise to 110 degrees in as little as four minutes. It's that dangerous, it's that fast," Jonh Van Zante of the Humane Society said.
It's not just pets in danger, but kids and the elderly as well. Van Zante points out that every summer, we hear of deaths linked to hot vehicles.