Onboard unit and driver information method

The present invention relates to an onboard unit for a vehicle (C i ) for informing the driver when traveling on a road section (S n ) with at least two adjacent driving lanes (T n,m ) forming a common traffic surface, wherein the onboard unit has a position detection device for determining its position and has a measured value of its speed (v), comprising a lane detector connected to the position detection device (5) with a map memory for a digital road map for locating a driving lane (T n,m ) corresponding to the determined position in the road map, a congestion detector for detecting traffic congestion when at least the speed measured value (v) falls below a predetermined threshold value, and an evaluation and output unit connected to the lane detector and the congestion detector, which is designed to output, upon detection of traffic congestion, travel direction information specific to the located driving lane (T n,m ).