Rising temperatures mean more deaths in hot cars, and Connecticut's senior senator says the federal government isn't doing enough to prevent them.

Sen. Richard Blumenthal says the Department of Transportation is three years late requiring carmakers to add a warning system for children left in the backseat.

Even on a cooler day like Monday, doctors say children can die inside a hot car.

"Today is a gorgeous day. It's 70 degrees or whatever it is, a beautiful breeze, but all of the cars around us are in the 115 to 120 range," said Dr. John Brancato with the Connecticut Children's Medical Center.

Some car manufacturers, like Toyota and Hyundai, have voluntarily added hot car alarms.