A Westborough teen died Sunday after the minivan he was driving crashed into sand-filled barrels, struck a concrete barrier, and rolled onto its side, trapping him inside, police said. Pablo C. Salcedo, 18, was driving a 2001 Dodge Caravan west on Route 9 when the crash occurred just after midnight Sunday near Speedway Plaza, police said in a statement. The force of the crash flipped the vehicle into the eastbound lane, where it collided with a 2008 Honda CRV, police said. The driver of the Honda, Srikrishnan Balasubramanian, 31, of Marlborough, was not injured. Firefighters removed Salcedo from the minivan; he was pronounced dead at the scene. Police said officers are investigating the crash and do not expect to bring any charges.