A Dallas police officer died Friday when his motorcycle struck a curb on the Houston Street viaduct as he was escorting Sen. Hillary Rodham Clinton to a rally in Oak Cliff. "One of our motorcycle jockeys rounded the curb, hit the curb, and went down," said Lt. Vernon Hale, spokesman for the Dallas Police Department. The officer's motorcycle was near the rear of the motorcade as it headed south on the viaduct when the accident happened about 9:20 a.m. Police identified the officer as Senior Cpl. Victor Lozada, 49, a 20-year veteran of the department. "There are no routine jobs...