A system, a control unit, and a method for deciding a geofence event of a vehicle is disclosed. The control unit includes (i) a first road information generation module configured to generate first road information based on received map data and vehicle location data, the first road information including at least one or more candidate lanes based on a vehicle location, (ii) a second road information generation module configured to generate second road information based on received radar data, the second road information including at least a detected lane based on the radar data, (iii) a calculation module configured to perform integrated calculation on the first road information and the second road information to obtain a confidence level of each candidate lane, and determine a lane of the vehicle based on the calculated confidence level, and (iv) a decision module configured to decide, based on the determined lane, whether to trigger a geofence event, the geofence event including an event that the vehicle enters a geofence and an event that the vehicle exits a geofence.