Methods and devices for controlling a vehicle in an autonomous mode are disclosed. In one aspect, an example method is disclosed that includes obtaining, by a computer system, lane information that provides an estimated location of a lane of a road on which a vehicle is traveling, where the computer system is configured to control the vehicle in an autonomous mode. The example method further includes determining, by the computer system, that the lane information has become unavailable or unreliable and, in response to determining that the lane information has become unavailable or unreliable, the computer system using at least one sensor to monitor at least one neighboring vehicle and controlling the vehicle to maintain a distance between the vehicle and the at least one neighboring vehicle to be at least a predetermined minimum distance.