When self-navigating automobiles encounter snow and ice, driving becomes tricky, say experts who believe obstacle detection technology has a long way to go before it can cope with the winter elements. “A lot of these vehicles use computer vision systems to look at the roadway ahead to understand where the lane boundaries are. When the road is covered in snow, they can’t see the lane boundaries,” said Steven Shladover, an advanced transportation researcher from the University of California, Berkeley.