KINERJA DAN RANCANGAN SIMPANG BERSINYAL TOL KRAPYAK SAMPAI DENGAN SIMPANG BERSINYAL PASAR JRAKAH SEMARANG Performance and Design of Krapyak Toll Road Signalized Intersection to “Pasar Jrakah” Signalized Intersection, Semarang

Abstract

Jalan Siliwangi menjadi gerbang utama keluar masuknya kendaraan di Kota Semarang dari arah Barat. Terlihat antrian kendaraan yang panjang di simpang-simpang bersinyal di ruas jalan ini. Antrian ini terjadi antara lain karena jarak antar simpang yang terlalu dekat dan pertumbuhan volume kendaraan yang semakin meningkat. Dari permasalahan yang terjadi, penulis mempunyai gagasan untuk mengkoordinasikan 3 (tiga) simpang yang letaknya relatif berdekatan, yaitu Simpang Bersinyal Tol Krapyak, Simpang Bersinyal Jalan Siliwangi-Jalan Gatot Subroto –Jalan Subali Raya, dan Simpang Bersinyal Pasar Jrakah, di ruas Jalan Siliwangi. Survai lalu lintas dilakukan terhadap ketiga simpang tersebut pada jam sibuk pagi dan jam sibuk sore pada hari yang berbeda, namun di hari kerja. Hasil survai kemudian diproses dengan program Kapasitas Jalan Indonesia (KAJI), Manual Kapasitas Jalan Indonesia (MKJI) 1997. Kinerja kondisi eksisting terjenuh akan menjadi dasar rancangan penanganan untuk jangka waktu pendek. Mula-mula kebutuhan waktu hijaunya disesuaikan dengan kondisi lalu lintas yang ada, kemudian dibuat penyesuaian berikutnya berupa pengaturan lalu lintas dan perubahan geometrik simpang untuk mengakomodasi kondisi lalu lintas yang ada. Dari kondisi penyesuaian arus lalu lintas dan geometrik jalan tersebut kemudian dibuat sebuah rancangan koordinasi antara ketiga simpang. Hasil analisis kondisi eksisting ketiga simpang tersebut telah menunjukkan kinerja dengan derajat kejenuhan rata-rata mencapai ≥ 0,8. Penyesuaian waktu hijau untuk tiap simpang pun tidak memberikan hasil yang memuaskan, karena menimbulkan waktu siklus yang terlalu panjang, yaitu 401 detik untuk peak hour pagi dan 491 detik untuk peak hour sore. Kemudian dengan dilakukan penyesuaian pengaturan lalu lintas dan perubahan geometrik simpang, kinerja ketiga simpang terlihat cukup baik. Dengan optimasi di masing-masing simpang itu, dilakukan koordinasi antara ketiga simpang, namun koordinasi ini terhambat oleh perbedaan jumlah fase diantara ketiga simpang, dimana Simpang Tol Krapyak memiliki 3 (tiga) fase, sedangkan yang lain hanya 2 (dua) fase. Dengan pertimbangan perbedaan jumlah fase, maka penulis memutuskan untuk mengkoordinasikan 2 (dua) simpang saja, dan juga karena kinerja Simpang I (Simpang Tol Krapyak) dianggap sudah cukup baik meskipun tanpa menggunakan koordinasi. Nilai efisiensi bandwidth peak hour pagi 55,32 % untuk arah Timur - Barat dan 54,25 % untuk arah Barat - Timur. Sedangkan untuk peak hour sore, efisiensi bandwidth untuk arah Timur – Barat sebesar 61,21 % dan untuk arah Barat – Timur 37,07 %. Rancangan yang dilakukan tersebut sudah cukup baik kinerjanya untuk tingkat penanganan untuk jangka waktu pendek. Sehingga, dapat disimpulkan bahwa kinerja simpang yang ditinjau menjadi lebih baik. Kata Kunci : Kinerja, Rancangan, Koordinasi, Bandwidth. ix PERFORMANCE AND DESIGN OF KRAPYAK TOLL ROAD SIGNALIZED INTERSECTION TO “PASAR JRAKAH” SIGNALIZED INTERSECTION, SEMARANG Abstract Siliwangi road is the west main gate of traffic to go inside and out from Semarang City. Inappropriate cycle time in each signalized intersections along this street and a large volumes of vehicle flow make a major lag inside this system. There are many vehicle trapped for a long time inside the system and also had a long queue. Based on that problems, we have an idea to coordinate 3 (three) signalized intersections that has a close distance proportion and being the major problem for the system, that is Krapyak Toll-road Signalized Intersection, Siliwangi Rd. – Gatot Subroto St. – Subali Raya St. Signalized Intersection, and “PasarJrakah” Signalized Intersection, along Siliwangi roadway. Traffic surveys conducted on the third intersection at peak hour morning and afternoon peak hour on different days, but on weekdays. Survey results will be processed using Capacity of Indonesia Highway (KAJI) program from Indonesian Highway Capacity Manual (IHCM) 1997’th. The solution design will be based on the performance of existing saturated condition. At start, the new cycle time of most exist saturated condition will be adjusted based on the traffic condition. Then from the adjustment result, we will make traffic management and some optimization from geometrical side in every intersection to accommodate the existing traffic condition. At last, we will design a coordination of group of signalized intersections to show its best performance. The result shows that the existing condition of all signalized intersections had an over-saturated flow more than 0.8 on average. Green time optimization for each signalized intersections does not shows the best performance. This result in a long cycle time, about 401 seconds in the morning peak hours and 491 seconds in afternoon peak hours. As we did the geometrical optimization in every intersection, the performance increased significantly. Therefore, the coordination scenario could be done. However, there are some problems to coordinate all of them. There is a signal phase difference between 3 (three) signalized intersection where Krapyak toll road signalized intersection only have 3 phase while the others has two phase. As Krapyak toll road signalized intersection had good performance, we decided to coordinate only two signalized intersections. The result of coordination scenario in this study is relatively acceptable, in this case is for an instant solution. In the morning peak hour, bandwidth efficiency is maximally clocked at 55.32% for east-west traffic and 54.25% for west-east traffic. In the afternoon peak hour, bandwidth efficiency is maximally clocked at 61.21% for east-west traffic and 37.07% for west-east traffic. Design that made it good enough for the level of handling performance for shortterm. So, it can be concluded that the performance of intersections that were reviewed for the better. Keyword : Performance, Design, Coordination, Bandwidth.