Abstract. The increasing of population will affect the number of vehicles. While the existing road is not be able to accommodate all vehicles that use certain areas, so that congestion occurs in various regions in large cities. Various alternatives have been developed by the Ministry of Public Works (PU) of the Republic of Indonesia on the design of traffic solutions to reduce traffic density. The roundabout is one of the traffic designs that developed by the Ministry of Public Works. The roundabout is a type of intersection without traffic lights where the traffic flows in one direction surround the roundabout in a clockwise direction by giving priority to the vehicles which get to the roundabout primarily. Modeling of the traffic flow at the roundabout is obtained by developing the transport model and the model of exits and entrances. By using the finite difference method, there will be several simulations of the traffic flow model. The results of simulations show the value of traffic density at roundabout which depends on the length of vehicles time in the roundabout, and to show more piling of vehicles in areas that have high traffic density values.Keywords: Roundabout, Traffic Flow Equation, Finite Difference Method.Abstrak. Bertambahnya jumlah penduduk akan mengakibatkan jumlah kendaraan yang meningkat tajam, sementara itu jalan yang ada tidak mampu menampung seluruh kendaraan yang menggunakan area jalan tertentu sehingga terjadinya kemacetan di berbagai wilayah di kota-kota besar. Berbagai alternatif yang dilakukan oleh kementerian pekerjaan umum (PU) Republik Indonesia terhadap desain solusi lalu lintas untuk mengurangi kemacetan telah banyak dikembangkan. Bundaran merupakan salah satu desain lalu lintas yang dikembangkan oleh kementerian PU. Bundaran adalah sebuah tipe persimpangan tanpa lampu lalu lintas dimana trafik berjalan dalam satu arah putaran mengelilingi sebuah bundaran searah jarum jam dengan memberikan prioritas kepada kendaraan yang terlebih dahulu berada di lintasan bundaran. Pemodelan arus lalu lintas pada bundaran didapat dengan mengembangkan model transport dan model keluar masuknya kendaraan. Dengan menggunakan metode Beda Hingga akan dilakukan beberapa simulasi terhadap model arus lalu lintas. Hasil yang diperoleh terlihat bahwa nilai kepadatan lalu lintas suatu bundaran bergantung pada waktu lamanya kendaraan di dalam bundaran, serta kendaraan yang semakin banyak menumpuk pada daerah yang memiliki nilai kepadatan lalu lintas yang tinggi.Kata Kunci: Bundaran, Persamaan Arus Lalu Lintas, Metode Beda Hingga.
Abstract. The increasing of population will affect the number of vehicles. While the existing road is not be able to accommodate all vehicles that use certain areas, so that congestion occurs in various regions in large cities. Various alternatives have been developed by the Ministry of Public Works (PU) of the Republic of Indonesia on the design of traffic solutions to reduce traffic density. The roundabout is one of the traffic designs that developed by the Ministry of Public Works. The roundabout is a type of intersection without traffic lights where the traffic flows in one direction surround the roundabout in a clockwise direction by giving priority to the vehicles which get to the roundabout primarily. Modeling of the traffic flow at the roundabout is obtained by developing the transport model and the model of exits and entrances. By using the finite difference method, there will be several simulations of the traffic flow model. The results of simulations show the value of traffic density at roundabout which depends on the length of vehicles time in the roundabout, and to show more piling of vehicles in areas that have high traffic density values.