Abstract: An apparatus and method are provided for identifying a preceding vehicle as a target vehicle in transient and non-transient situations. The method generally includes, estimating a position of the target vehicle relative to a position of an ACC vehicle from the position of the ACC vehicle to create a target vehicle estimated position; creating a time-dependent position trace of the target vehicle; estimating a radius of the position trace of the target vehicle by applying circular curve fitting to the position trace of the target vehicle; and determining whether the target vehicle is in an ACC vehicle lane using the radius of the position trace, the target vehicle estimated position and the position of the ACC vehicle.