1. A method of verifying or filling in attribution associated with segments of transportation networks that are digitally mapped from a digital transportation network database, said method comprising: analyzing the database to identify at least one attribute of interest that is missing or whose accuracy is unreliable and further identifying at least one segment in question of the transportation network with which the attribute of interest is associated; further analyzing the database to identify a first segment of the transportation network and a second segment of the transportation network, wherein the first segment is immediately preceding and connected to a front end of the at least one segment in question and the second segment is immediately succeeding and connected to a back end of the at least one segment in question, and further wherein the first and second segments have associated attribution of interest that is determined to be accurate; gathering a plurality of probe traces from users of probe-transmitting personal navigation devices that have traversed the at least one segment in question as well as traversed the first and second segments on either side of the at least one segment in question, wherein the probe traces include probe-derived attribute information; and determining whether the probe-derived attribution information is reliable, and if so, comparing the trend of the probe-derived attribute information of the first and second segments with the trend of the database attributes of the first and second segments, and if there is a positive correlation, populating the attribution from the first and second segments based on correlation to the database for the at least one segment in question to fill in the missing or verify the unreliable database attribution for the at least one segment in question.