A method, apparatus and computer program product are provided to disambiguate probe points within an ambiguous probe regions to permit more reliable association with a road segment. In regards to a method, probe trajectory identifiers (IDs) of probe points along at least a portion of the first and second branches that lead away from an ambiguous probe region are separately identified and form first and second sets of probe trajectory IDs, respectively. For the ambiguous probe region, the probe trajectory IDs of probe points along a third branch that leads toward the ambiguous probe region are identified and form a third set of probe trajectory IDs. The method also includes classifying probe trajectory IDs from the third set as being associated with the first branch or the second branch in an instance in which the probe trajectory IDs are additionally included in the first set or the second set, respectively.