The head of the US government's Hurricane Katrina relief efforts made a surprise visit to a newly built trailer park Saturday and said hundreds of similar makeshift towns are planned to house residents displaced by the storm. US Coast Guard Vice Adm. Thad Allen called the construction of the park, which holds more than 570 trailers about 91 miles (146 kilometers) northwest of New Orleans, "pretty remarkable." The park is laid out like a small town, with gravel roads, street lights and power lines. Allen said about 120,000 trailers and mobile homes are expected to be delivered to Louisiana for evacuees in the coming weeks. The optimum size of each park will be about 200 housing units, but they also may be placed on the property of residents with destroyed homes, he said. Other people may wind up in hotels, he said.