T Tangerang is located in a strategic spot to the west of Jakarta Supporting its strategic location is the accessibility to the central core of Jakarta, Soekarno - Hatta International Airport, Tanjung Priok Harbour at Jakarta, Bojonagara Harbour at Cilegon and others city around Jabotabek and West Java Its strategic location result in fast growth and expansion such as the development of settlement area, industrial area and commercials areaThe problem of traffic condition in Tangerang is worse, marked with thelarge numbers of traffic volume exceed its roads capacity, mainly on Daan Mogot- Gatot Subroto roads, which are the premier arterial road connecting Cilegon,Tangerang and Jakarta These primary arterial roads have function not only serving and holding through traffic but also serving internal traffics and external traffics of its surrounding town, which currently have bad serving performance.The traffic problems occurred on Daan Mogot - Gatot Subroto roadscaused by government construction, such as development of new road network, city spatial planning along with social economic politic considerations which need times and costly, undisciplined driver and ineffective road management. These traffic problems can be handled through identification of traffic problems, to which preliminary study on factors affecting the decreasing in level of service on both roads is carried out In this study , the level of problems are limited on the assessment of roads level of services.The system used in identifying the factors affecting the decreasing in level of service is the system analysis through macro and micro analysis (policy system). These analysis are:Activity system of type of activity (land activity) Network system (traffic management) Movement system (traffic performance)Policy system (government regulation)The assessment of road serving ability in this study is focused on the variable of volume ratio to the capacity with speed variable.The aim of study is to identify factors affecting the decreasing in level of service on the primary arterial roads and provide micro recommendations derive from policy system. The results of the study are as follows:• Factors affecting the decreasing in level of service:The influence of policy. system include. transportation policy system of Tangerang that covers road network, public road railway transport and terminals freight goods transport and parking which had been well planned, but not implementation well and fast, traffic management policy not in line with the traffic policy also the restriction of local governmentvfund, minimum cooperation within the interrelated institutions in solving the traffics problems.The influence of activity system include the high building intensity andland use planning (CBD, Industry, building spot, terminal, school and signage).The influence of network system include interchange design, inconsistentroad hierarchy, invasion toward roads area, types vehicle.• Recommendations through traffics problem solving on Daan Mogot - Gatot Subroto roads are as follows:J> Macro recommendations (policy system)Development of alternative roadsImprove the quality and quantity of railway transportApplication of transport development planningIntegrated government policy towards traffic managementPolicy in spatial planning in order to keep function of premier arterial road.J> Micro recommendations (activity system and network system), there areseven nodes, so that the following steps are needed:Node I : repairing interchange design, constructing traffic lights, managing traffic circulation, managing road vendors, managing market.Node 2 : repairing interchange design; managing traffic, constructing traffic light..Node 3 : Managing predicable and motorcycle transport stations,• constructing traffic light, managing traffic.Node 4 : Managing traffic circulation, constructing traffic light (ATCS system), managing traffic.Node 5 : Managing street vendors, managing trade center/market, Dissmiss the temporary station function.Node6Node7: Constructing traffic lights, repairing interchange design.: Closing the U-Tum traffic flows, managing traffic.