Do you mean Rest Areas on the interstate highways or places to rest that are areas? There are probably are some bad Rest Stops on interstates, but most will be safe enough, but beware that some states, TN for ex, only allow you to stop a few hours, they are rest, not sleep, but if you get a ticket so what, you will be back in another country and eventually the parking ticket will be sold to a collection agency who will not be able to collect. I would look for busineess that allow overnight parking instead, like Cracker Barrel.