A 51-year-old woman died late Monday when her minivan went off a road and struck a tree head-on about 3 miles west of Ellendale, state police reported this afternoon. A family dog in the van also died. Police said the accident happened about 10:15 p.m. on Del. 16 (Beach Highway) about 1/10 mile east of Oakley Road. Sgt. Walter Newton said police don’t know why Johnson’s 2001 Chrysler Town & Country minivan, which was eastbound, went off the westbound side of the road. The crash caused the engine to separate and land 30 feet from the point of impact with the tree, he said. The minivan then bounced back into the westbound lanes of the highway. Alcohol use is not suspected, Newton said. He said She was not wearing a seat belt.