Originally Posted by Potty_Pants
they are designed to allow you to drive a resonable distance to get the car tire fixed. They are designed to allow you to safely navigate a busy highway and find a safe garage/tire shop to fix immediately following the puncture.
The only problem with this is that I have never heard of any shop fixing a punctured RFT - they always say you have to replace it. I thought I remembered reading that the shops didn't want the liability because they couldn't tell how far the car had been driven on a flat.