Check the backseat 

Every year dozens of children die in the United States after being left alone in a hot vehicle. Tammy Carlsrud of Norman Mahnomen Public Health reminds parents to check the back seat, and not leave children in your vehicle unattended. 

Leaving children in a vehicle unattended is a crime in many states. If you see a child in a car unattended contact law enforcement and emergency medical services if the child is showing signs of heatstroke.