for (int i = 0; i < stop_services.size(); ++i)
    {
        if (!service_usage.at(i)) continue;
        int stopServiceId = stop_services.at(i)->stop_service_id();

        float nextSlUsage = (slUsage == 1) ? 1.0 :
            path->get_stop_service_total_sl_usage(legnr-1, stopServiceId);
        if (!nextSlUsage) continue; // [5/27/2009 jamie.cook] TODO: should this be a break here or after we populate m_nextLoadAtStopService?

        if (!m_nextLoadAtStopService.at(stopServiceId))
        {
            nextStopServiceList.push_back(stop_services.at(i));
            if (doingSl) nextStopServiceSlUsage.push_back(nextSlUsage);
        }
        float usageTimesLoad = service_usage.at(i) * load;
        m_nextLoadAtStopService.at(stopServiceId) += usageTimesLoad;

        // [5/27/2009 jamie.cook] TODO: should this be usageTimesLoad * (slUsage || nextSlUsage) ??
        ptLoad->IncrementInterchange(nextStopService, stop_services.at(i),
            usageTimesLoad * slUsage);
    }