STILLWATER, Okla. — Three people were killed and 34 others were injured on Saturday when a car plowed into a crowd during Oklahoma State University’s homecoming parade, the authorities said.  The scene unfolded around 10:30 a.m. near the end of the parade at an intersection two blocks from the stadium where Oklahoma State was set to play the University of Kansas in the homecoming football game. The driver of a Hyundai Elantra struck an unmanned police motorcycle before plowing into the crowd, Capt. Kyle Gibbs of the Stillwater Police Department said.  All of those injured were being treated at Stillwater Medical Center. Eight were in critical condition, including seven who had been airlifted to the hospital, city officials said in an afternoon update. Nine people were seriously injured, and 17 others were described as “walking wounded.”  The driver, identified as Adacia Avery Chambers, was arrested on charges of driving under the influence, the police said. Ms. Chambers, 25, of Stillwater, was in jail on Saturday, according to Captain Gibbs. She is not an Oklahoma State student, he said.  Accident investigators were still working at the crash scene Saturday afternoon, and said they had not determined if the act was intentional. The crumpled front of the gray Hyundai could be seen at the intersection. A baby stroller stood a few feet away. Several people dressed in the school colors, orange and black, were seated on the ground being tended to by emergency medical workers. Yellow caution tape and orange traffic cones surrounded the area.  Witnesses described seeing a fast-moving sedan and bodies flying, according to news reports.  “At first we thought it was part of the show,” Konda Walker, a 1991 Oklahoma State graduate who was visiting from Anchorage, told The Stillwater News Press. “People were flying 30 feet into the air like rag dolls.”  At the news conference, Oklahoma State’s president, Burns Hargis, said the game against Kansas would be played as scheduled on Saturday afternoon.  “The decision was made that we’re going to play, and we’re going to remember the victims at the game,” he said. “We’re going to move forward, but we will remember what happened today.”  In a statement on Twitter, Oklahoma State said it was “saddened by the tragic parade incident earlier this morning.”  “Our thoughts and prayers are with those affected,” it added.  Oklahoma State boasts that it hosts the nation’s largest homecoming gathering, annually drawing tens of thousands of visitors for a weekend of celebration. Stillwater, which sits between Oklahoma City and Tulsa, about 70 miles from each, has a population of about 47,000, but local officials say as many as 80,000 visitors descend on the city for homecoming weekend.  Kathleen McElroy reported from Stillwater, and Ashley Southall from New York.  A version of this article appears in print on October 25, 2015, on page A21 of the New York edition with the headline: Car Plows Into Crowd At Oklahoma State, Leaving Three Dead . Order Reprints| Today's Paper|Subscribe
At least 22 others were injured in the accident during the university’s homecoming parade. A woman was charged with driving under the influence.