This is a FEMA (Federal Emergency Management Agency) trailer. FEMA is part of the U.S. Department of Homeland Security--a group that aids in recovery from natural and man-made disasters, like earthquakes or war. FEMA has been criticized with the way they handled Hurricane Katrina.
These trailers were supposed to be used as housing for those who lost their homes. However, during our trip we saw thousands just sitting there empty--even though there is a waiting list to get a trailer.