The eight-lane Interstate 35W bridge, a major Minneapolis artery, was in the midst of being repaired and two lanes in each direction were closed when the bridge buckled. About 20 families gathered at an information center, looking for information on loved ones they couldn't locate. "There were two lanes of traffic, bumper to bumper, at the point of the collapse. Those cars did go into the river," said Minneapolis Police Lt. Amelia Huffman. "At this point there is nothing to suggest that this was anything other than a structural collapse." By 1 a.m. Thursday, Hennepin County Sheriff Rich Stanek said all search efforts had been called off for the night and that searchers did not expect to find any survivors in the at least 50 vehicles still in the water.  "It's dark, it's not safe with the currents in the water and the concrete and rebar," he said. "At this point it is a recovery effort." The Homeland Security Department also said the collapse did not appear to be terrorism-related. The National Transportation Safety Board planned to send a team of investigators to Minneapolis, NTSB spokesman Ted Lopatkiewicz said.  Gov. Tim Pawlenty said the bridge was inspected by the Minnesota Department of Transportation in 2005 and 2006 and that no structural problems were noted. "There were some minor things that needed attention," he said. "Obviously, this is a catastrophe of historic proportions for Minnesota," said Pawlenty said. "And right now we are focused on making sure that we are doing everything to respond to the needs of those individuals that may have been harmed in this incident." The Associated Press contributed to this story.