A University of New Hampshire student was seriously injured after he was hit while crossing Main Street in Durham.The Durham Police Department said the student, a 21-year-old from Bedford, was in the crosswalk between Depot Road and Sage Way when he was hit just before 6:30 p.m. Tuesday.The pedestrian was taken to Portsmouth Regional Hospital and then by medical helicopter to Maine Medical Center. The driver of the vehicle, a 21-year-old from Franklin, Massachusetts, also a UNH student, was not injured, stayed at the scene and is cooperating with the investigation, police said. Police said speed and impairment do not appear to be factors.