When the new Interstate 35W bridge opens next week in Minneapolis, it will have a one-of-a-kind safety feature.More than 300 sensors are buried in the bridge's concrete.Those sensors will gather information that will be used to gauge wear and tear.Scientists will be able to tell how much the bridge moves during heavy traffic periods and during bad weather.They will also know if the bridge is corroding.The system is called Smartbridge technology.Tom Jenkins Junior, Figg Engineering, says, ''We'll be a very good tool for everybody to know how the bridge is performing, long before problems arise.''Officials with the Minnesota Department of Transportation say that even with the new technology, they will continue to perform visual inspections.