1. A computer-implemented method for assessing data samples representing vehicles traveling on roads, the method comprising: receiving, by one or more computing systems configured to assess traffic information, and for each of one or more road segments of one or more roads, multiple associated data samples that each are reported by one of multiple vehicles and indicate a reported location of the vehicle that corresponds to the road segment; and for each of at least one of the road segments, automatically analyzing, by the one or more configured computing systems, the multiple associated data samples for the road segment to determine one or more data samples that are a subset of the multiple data samples and that are unrepresentative of actual vehicle travel on the road segment, at least one of the determined data samples each indicating a reported location for the vehicle reporting the data sample that does not correspond to the actual vehicle travel on the road segment, and at least one of the determined data samples each having an associated heading for the vehicle reporting the data sample that does not correspond to the actual vehicle travel on the road segment; and providing, by the one or more configured computing systems, one or more indications to exclude the determined data samples from later use, to enable using other of the multiple associated data samples for the road segment in facilitating travel on the road segment.