std::pair<MSVehicle* const, SUMOReal>
MSLaneChanger::getRealThisLeader(const ChangerIt& target) const {
    // get the leading vehicle on the lane to change to
    MSVehicle* leader = target->lead;
    if (leader == 0) {
        MSLane* targetLane = target->lane;
        MSVehicle* predP = targetLane->getPartialOccupator();
        if (predP != 0) {
            return std::pair<MSVehicle*, SUMOReal>(predP, targetLane->getPartialOccupatorEnd() - veh(myCandi)->getPositionOnLane());
        }
        const std::vector<MSLane*>& bestLaneConts = veh(myCandi)->getBestLanesContinuation();
        MSLinkCont::const_iterator link = targetLane->succLinkSec(*veh(myCandi), 1, *targetLane, bestLaneConts);
        if (targetLane->isLinkEnd(link)) {
            return std::pair<MSVehicle*, SUMOReal>(static_cast<MSVehicle*>(0), -1);
        }
        MSLane* nextLane = (*link)->getLane();
        if (nextLane == 0) {
            return std::pair<MSVehicle*, SUMOReal>(static_cast<MSVehicle*>(0), -1);
        }
        leader = nextLane->getLastVehicle();
        if (leader == 0) {
            return std::pair<MSVehicle*, SUMOReal>(static_cast<MSVehicle*>(0), -1);
        }
        SUMOReal gap =
            leader->getPositionOnLane() - leader->getVehicleType().getLength()
            +
            (myCandi->lane->getLength() - veh(myCandi)->getPositionOnLane() - veh(myCandi)->getVehicleType().getMinGap()); // !!! recheck
        return std::pair<MSVehicle* const, SUMOReal>(leader, MAX2((SUMOReal) 0, gap));
    } else {
        MSVehicle* candi = veh(myCandi);
        SUMOReal gap = leader->getPositionOnLane() - leader->getVehicleType().getLength() - candi->getPositionOnLane() - candi->getVehicleType().getMinGap();
        return std::pair<MSVehicle* const, SUMOReal>(leader, MAX2((SUMOReal) 0, gap));
    }
}