A method for estimating an effective length of a first vehicle segment of a vehicle combination, the vehicle combination comprising a towing vehicle which is connected to the first vehicle segment via a first articulation joint and a perception sensor mounted on one of the towing vehicle and the first vehicle segment and arranged to obtain an image of the other one of the towing vehicle and the first vehicle segment; the method comprising identifying that the vehicle combination is provided in a first steady vehicle state, identifying that a turning and driving manoeuvre is initiated, identifying when the vehicle combination reaches a second steady vehicle state, determining a time period required for driving the vehicle combination from the first steady vehicle state to the second steady vehicle state, and estimating the effective length by use of the time period, the specific angular change, and the specific speed.