Evaluation the Effect of Roundabouts’ Geometric Elements on Intersection Safety in the Light of Literature

Öz

Intersections, which have a great role in the safe and effective operation of traffic in the transportation system, are categorized according to their grade level, geometric properties, and control type. A roundabout is the type of grade level intersections, in which vehicle passages around the island are provided through circulatory roadway and vehicles gives priority to the traffic around the island. Each geometric element of roundabouts plays a role in the operation, capacity and safety of the roundabout. A well-designed roundabout helps optimize intersection safety by ensuring that vehicles' speeds remain constant along the circulatory roadway. This article examines the effects of geometric elements of roundabouts on intersection safety. In the light of the studies in the literature each geometric element of the roundabouts, the relationship with the intersection safety and the design criteria included in the standard/guidelines of some countries are investigated. The aim of this study is to demonstrate that the designs of roundabouts geometric elements are of crucial importance in terms of intersection safety. The lack of detailed studies on this subject in our country has been the motivation of our study. It is also seen that there is a lack of information about which roundabouts are built depending on the standards/guidelines in our country. As a result of the study, it was stated that geometric elements should be designed in roundabouts with each other and proper physical dimensions to ensure safety at roundabouts. In addition, it is stated that in terms of traffic safety, work on this subject should be started immediately and the design standard/manual specific to the conditions of our country should be prepared.

Anahtar Kelimeler

• Roundabout,roundabout geometry,safety,geometric design

Dönel Kavşak Geometrik Elemanlarının Kavşak Güvenliği Üzerine Etkisinin Literatür Işığında Değerlendirilmesi

Öz

Ulaşım sistemi içerisindeki trafik akımının güvenli ve etkin biçimde işlemesi üzerinde büyük rolü bulunan kavşaklar, faaliyet alanı, geometrik özellikleri ve denetim şekillerine göre farklı kategorilere ayrılmaktadır. Kontrollü eş düzey kavşak kategorisindeki dönel kavşaklar, trafik akımının merkezi ada etrafında yönlendirildiği ve ada içerisindeki araçların ilk geçiş hakkına sahip olduğu kavşak tipidir. Dönel kavşakların her bir geometrik elemanı kavşağın işleyiş, kapasite ve güvenliği üzerinde rol oynamaktadır. İyi tasarlanmış bir dönel kavşak, araçların dolaşım yolu boyunca hızlarının sabit kalmasını sağlayarak kavşak güvenliğinin optimize edilmesine yardımcı olur. Bu makalede, dönel kavşakların geometrik elemanlarının kavşak güvenliği üzerine etkilerinin incelendiği çalışmalar derlenmiştir. Dönel kavşakların her bir geometrik elemanın literatürde yer alan çalışmalar ışığında kavşak güvenliğiyle olan ilişkileri ve bazı ülkelerin standart/kılavuzlarında yer alan tasarım kriterleri incelenmiştir. Bu çalışmayla amaçlanan, yapılmış çalışmalar doğrultusunda, dönel kavşak geometrik elemanlarının tasarımlarının kavşak güvenliği açısından hayati önem taşıdığını ortaya koymaktır. Ülkemizde bu konuyla ilgili olarak daha önce yapılmış detaylı çalışmalara rastlanılmaması çalışmamızın motivasyon kaynağı olmuştur. Ülkemizdeki dönel kavşakların hangi standart/kılavuzlara bağlı olarak yapıldığı ile ilgili bilgi yetersizliği olduğu da görülmektedir. Çalışma sonucunda dönel kavşaklardaki güvenliğin sağlanabilmesi için geometrik elemanların birbirleriyle etkileşim içinde ve uygun fiziki boyutlarda tasarlanması gerektiği belirtilmiştir. Ayrıca trafik güvenliği bakımından ülkemizde bu konuyla ilgili ivedilikle çalışmalara başlanılması ve ülkemiz koşullarına özgü tasarım standart/kılavuzu hazırlanması gerektiği ifade edilmiştir.  

Anahtar Kelimeler

• Dönel kavşak,kavşak geometrisi,güvenlik,geometrik tasarım

Kaynakça

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