General Motors will introduce in two years its first car that can communicate with other vehicles to help avoid accidents and ease traffic congestion, Chief Executive Mary Barra said on Sunday. In the same time frame, GM also will introduce more advanced technology allowing hands-free driving in some cases, she said. “I’m convinced customers will embrace vehicle-to-vehicle and automated driving technologies for one simple reason: they are the answer to everyday problems that people want solved,” she said in a text of a speech delivered at a conference here.