Researchers are working on this in Michigan. The University of Michigan has a new MCity test facility[0], and I know one of the projects they are working on is how the cars handle snow. They basically still do LIDAR and match the z-plane (height of objects nearby) to localize the car when road markings are hard to see.<p>Still lots of work to do though!<p>[0]: <a href="http:&#x2F;&#x2F;www.mtc.umich.edu&#x2F;test-facility" rel="nofollow">http:&#x2F;&#x2F;www.mtc.umich.edu&#x2F;test-facility</a>