If a street is extremely crowded to an extent that the terrain is not visible from the point of view of the LIDAR (e.g. in google's self driving car), can it still manage to localize itself and continue to operate? I recall Sebastian Thrun saying that Google's car cannot navigate through snow filled roads since the onboard LIDAR cannot map the terrain beneath the snow (e.g. here).
[Edit : Based on the comments] Clarifying the context, here "not visible" means there is an obstacle between the LIDAR and the terrain