Truck platooning is seen as a method to reduce truck emissions and labor hours in the transport industry. The effect that truck platooning will have on the other traffic receives less attention. In this thesis a methodology is proposed to model truck platoons, including a platoon level controller for lane changing. The model is used to estimate the on-ramp length that vehicles require in order to safely merge into the highway while interacting with platoons and the model is used to estimate the on-ramp length that truck platoons require in order to merge onto the highway if they would do so in platoon formation. Results show that onramps need to be at least 300 meters for other traffic to safely into the highway. For platoons to safely merge into the highway the required distance is heavily dependent on the crowdedness of the highway, ranging between 400-1000 meters of required on-ramp length.