37-year-old Stephen Williams, of Pacifica, was arrested for DUI following a 4-vehicle crash, Saturday afternoon that caused multiple injuries. Williams was westbound on Highway 20, approaching Sulphur Bank Drive at a high rate of speed. He collided with the rear of the vehicle in front of him. Williams then struck two vehicles in the eastbound lane. He suffered major injuries. One of the eastbound drivers had major injuries and was flown to a hospital for treatment, along with two young girls, ages 1 and 2, who were passengers. They had minor injuries.