DENVILLE - Officials in the Garden State are issuing a warning to residents to never leave children, the elderly or pets inside of cars when temperatures become too warm.

At an event in Denville Monday, advocates demonstrated how quickly temperatures can rise inside a car when it is turned off and the windows are closed. Temperatures reached the low-90s in New Jersey and the demonstration showed that temperatures inside cars rise to well over the temperatures outside.

"Spread the word, share your knowledge. If you see a child, an elder or a dog or another pet left in a vehicle, please call 911.  One call can save a life,” says Morristown Medical Center’s KJ Feury.

Officials say that in the past year over a dozen children across the country have died from being left inside an overheated car. None of those cases were in New Jersey. Experts say that a child’s body can heat up three to five times faster than an adult’s.

Experts also say that opening up a window slightly does not make a difference and it does not even have to be very hot outside for the temperature inside the car to reach unsafe levels. They say it is best to never leave anyone inside a locked-up car.