<![CDATA[Permasalahan kemacetan lalu lintas di Kota Medan semakin meningkat seiring dengan pertumbuhan jumlah kendaraan bermotor, khususnya pada persimpangan Jalan Gatot Subroto dengan Jalan Gagak Hitam/Ring Road. Penelitian ini bertujuan untuk menganalisis efektivitas pembangunan underpass dalam mengurangi kemacetan serta meningkatkan kinerja lalu lintas di kawasan tersebut. Metode yang digunakan adalah Before–After Study (sebelum–sesudah) dengan pendekatan kuantitatif berdasarkan pedoman Direktorat Jenderal Bina Marga (MKJI 1997). Data yang dianalisis merupakan data primer hasil survei lalu lintas pada jam puncak sore (16.00–19.00), meliputi volume kendaraan, Lalu Lintas Harian Rata-rata (LHR), derajat kejenuhan (DS), dan tingkat pelayanan jalan (LOS). Data sebelum dan sesudah pembangunan underpass kemudian dibandingkan untuk mengetahui perubahan kinerja lalu lintas. Hasil penelitian menunjukkan bahwa pembangunan underpass memberikan dampak positif terhadap kelancaran lalu lintas, yang ditandai dengan penurunan nilai LHR serta membaiknya derajat kejenuhan dan tingkat pelayanan jalan. Dengan demikian, underpass dapat menjadi solusi efektif dalam mengurangi kemacetan di kawasan perkotaan. Traffic congestion in the city of Medan has been increasing in tandem with the growing number of motor vehicles, particularly at the intersection of Gatot Subroto Street and Gagak Hitam Street/Ring Road. This study aims to analyze the effectiveness of constructing an underpass in reducing congestion and improving traffic performance in that area. The method used is a Before–After Study with a quantitative approach based on the guidelines of the Directorate General of Highways (MKJI 1997). The analyzed data consists of primary data from traffic surveys conducted during the evening peak hours (4:00 PM–7:00 PM), including vehicle volume, Average Daily Traffic (ADT), degree of saturation (DS), and Level of Service (LOS). Pre- and post-underpass construction data were then compared to determine changes in traffic performance. The results of the study indicate that the construction of the underpass has a positive impact on traffic flow, as evidenced by a decrease in ADT and improvements in the degree of saturation and level of service. Thus, underpasses can serve as an effective solution for reducing traffic congestion in urban areas.]]>
