A navigation system (20, 50) comprising: a communication interface configured to receive virtual probe data from a plurality of sources, wherein the virtual probe data comprises a plurality of virtual probe points at different respective locations, wherein, for a virtual probe point, the virtual probe data comprises a hashed license plate information of a vehicle and a location of the vehicle, and wherein the hashed license plate information of the virtual probe data that is received have been subjected to a same hash function by each of the plurality of sources, and wherein a virtual probe point is captured and provided by a data collection device onboard and carried by another vehicle that is generally proximate to or at least sufficiently near the vehicle that is the subject of the virtual probe point such that the vehicle that is the subject of the virtual probe point is visible from the vehicle carrying the data collection device; and at least one processor configured to analyze the hashed license plate information of the virtual probe points provided by different sources to identify a same vehicle at different locations at different times and, based on identification of the same vehicle at different locations at different times, to estimate traffic conditions; wherein the at least one processor is configured to estimate traffic conditions by determining a most likely route between the different locations and: (i) estimating a distance traveled by the vehicle along the most likely route between the different locations; and/or (ii) determining an average speed of the vehicle along the most likely route between the different locations. a communication interface configured to receive virtual probe data from a plurality of sources, wherein the virtual probe data comprises a plurality of virtual probe points at different respective locations, wherein, for a virtual probe point, the virtual probe data comprises a hashed license plate information of a vehicle and a location of the vehicle, and wherein the hashed license plate information of the virtual probe data that is received have been subjected to a same hash function by each of the plurality of sources, and wherein a virtual probe point is captured and provided by a data collection device onboard and carried by another vehicle that is generally proximate to or at least sufficiently near the vehicle that is the subject of the virtual probe point such that the vehicle that is the subject of the virtual probe point is visible from the vehicle carrying the data collection device; and at least one processor configured to analyze the hashed license plate information of the virtual probe points provided by different sources to identify a same vehicle at different locations at different times and, based on identification of the same vehicle at different locations at different times, to estimate traffic conditions; wherein the at least one processor is configured to estimate traffic conditions by determining a most likely route between the different locations and: (i) estimating a distance traveled by the vehicle along the most likely route between the different locations; and/or (ii) determining an average speed of the vehicle along the most likely route between the different locations. (i) estimating a distance traveled by the vehicle along the most likely route between the different locations; and/or (ii) determining an average speed of the vehicle along the most likely route between the different locations.