An approach is provided for estimating a vulnerable road user count in real time or near real time. The approach, for example, involves collecting one or more vulnerable road user observations from at least one vehicle traveling a road link. The approach also involves querying a geographic database for historical vulnerable road user data for the road link. The approach further involves determining a first variance for the one or more vulnerable road user observations and a second variance for the historical vulnerable road user data. The approach further involves calculating the vulnerable road user count by fusing the one or more vulnerable road user observations with the historical vulnerable road user data based on the first variance and the second variance.