H. R. 8884, known as the “Peggy Frank Memorial Act,” mandates that all delivery vehicles used by the United States Postal Service must have climate control units. Existing vehicles must be modified to include these units within three years from the enactment of this bill....
Simple Explanation
The Peggy Frank Memorial Act says that the mail trucks used by the post office need to have air conditioning or heating, so the people delivering mail feel comfortable. It's like making sure their cars have a way to keep them warm or cool, just like how some houses have heaters or air conditioners.