الگوي مناسب براي انتخاب نوع تقاطع هاي غيرهمسطح و تبادل ها

A proper pattern to select unlovely intersections and interchangesʹ type

Leveled intersec tions are areas with the mos t inc ident s, most fue l usage, and mos t ecological pollution. Today, it is necessary to eo nvcrt leveled intersec tion to interchanges, regarding expanding the ci ties, increasing vehicle s and to decr ease traffic problem s. Select ing the interchange type [or a spcci fie area is very complex and is depend ing on factors suc h as traffi c type, intersection position, topography situatio n, needed limit to co ns truct, ecological and economica l con cerns. Here, in this study, afte r introd uction ofintcrchangcsʹ types and comparison ofthei r functions, we present a pattern to se lect interch angesʹ typ es for inner and outer city routes. At inne r city rou tes it is difficult to selec t, because of complexities and unw ished problems such as lack o f needed limits,. .. but at outer city routes it is easy to selec t, due to the traffi c type an d speed of co llisio n parts. Finally, gu iding interchanges are the best psychol ogica lly, but have the most cos t to co nstruct. Complete clove r interchange is the best choice to co nnect free ways, but it is impo rtant to co nsider interfere ntia l area . Urban single spot interchange can also be the first choice for urban area s, specially where there is one main and other minor route. Lozenge interchange can be a choice for urban areas , due nee d to a few construct ion lim it, but it is important to consid er left-tum movements in this in terchange.