State Police said eight Dartmouth College students escaped injury when the van they were in rolled over after hitting a patch of ice on Interstate 91 in Vernon. Police said rescue crews were called about 7:15 a.m. Friday to an area about 5 miles north of the Massachusetts line. Police said the van was carrying members of Dartmouth’s Ultimate Frisbee team, who were headed to a tournament in Virginia. The van went off the left side of the road, hit an embankment, and came to rest on its side. All occupants were wearing seat belts.