In your head, move the decimal point one number to the right and you have a 40-inch wide door.
We scale all of our templates to the manufacturer specifications of each vehicle. You can also measure your estimated print panels with the ruler tool in Photoshop or Illustrator to further refine your square footage estimates. The templates are in the tenth scale, so while you're designing your wrap, you would use the smaller setting of the template. When you are preparing to print you can set the resolution and dimensions to full size.
Here's an example, you are working on a Chevrolet Silverado pickup, the size is 20 by 9 at 720 ppi, which is the small setting, you do your design work at.