A system for a vehicle operating on a road includes a vehicle placement module that references, based on a geographic position of the vehicle, a road mapping database to identify a selected lane of the road where the vehicle is located. A lane assignment module (i) receives information indicating identification of an object in the road and (ii) determines a relative lane of the object with respect to the selected lane. A curvature plotting module determines a curvature line of the selected lane. An object placement module (i) determines a first distance value representing a shortest distance between the object and the curvature line and (ii) determines whether the relative lane of the object is the selected lane based on the first distance value and a lane width value. An alert generation module selectively generates an alert signal in response to the object being in the selected lane.