Travel restrictions have a very limited benefit for the place imposing them when the virus is already spreading somewhere. U.S. restrictions on travel from China, and from Europe, came after they were too late to matter.
Yet they haven’t come domestically. That may be one of the bigger risks we face as different areas of the country struggle to overcome the spread of the novel coronavirus on different timelines. We’re seeing restrictions on domestic travel in places that are dealing relatively well with the virus (Australia) and those that have suffered greatly (Italy).