A method for traffic state estimation of a road network based on a plurality of vehicles including probe vehicles and non-probe vehicles travelling includes receiving probe vehicle data from the probe vehicles within a communication range of a host vehicle. The method also includes spatially and temporally associating the probe vehicle data to lane level cells of the road network, and identifying empty lane level cells of the road network where the probe vehicle data is unavailable. The method includes calculating estimated non-probe vehicle data for the empty lane level cells based on the probe vehicle data. The method further includes calculating a traffic density value for the road network based on the probe vehicle data and the estimated non-probe vehicle data and providing the traffic density value to the host vehicle.