Hot cars are death traps for dogs, even with windows slightly open or in the shade in temperatures as low as 70 degrees. If a dog is barking, yes he/she is alive, but it can also be a sign of distress.
The last time I saw dogs in a car was a couple of months ago, I waited for the owner to come back. I did not have my phone and was waiting for someone to walk by with a phone to help when luckily the owner showed right up. I told him to please get the dogs out which he did. He started talking about how they barked everywhere he took them so he left them in the car. I explained the heat issue - the car is much hotter than outside - but I could not tell how he felt about my doing all that. I worried for those dogs and actually still pray for them and the owner - he was upset. The one in the back that was just lying there (stopped the constant barking at me and just lay down and stopped moving) came right up to me when it got out. I honestly think I saved that dog’s life. There was another one on a leash in the front. The guy realized how hot the car was - he was freaking out.
If you have dogs, please don’t do this - don’t take the dog in the car on a hot day or on errands. Leave it at home.
Here is what the Human Society recommends if you see a dog trapped in a car:
If the owner can’'t be found, call the non-emergency number of the local police or animal control and wait by the car for them to arrive. In several states good Samaritans can legally remove animals from cars under certain circumstances, so be sure to know the laws in your area and follow any steps required.