Ali MansourKhaki - Associate Professor, Iran University of Science and Technology, Mkhaki@iust.ac.ir
Kianoush Siamardi - Master of science Student,Road & Transportation, Islamic Azad University, South Tehran
Omid Rahmani - Master of science Student,Road & Transportation, Islamic Azad University, South Tehran
Morteza Tolouei - Bachelor of science, Civil Engineering, Islamic Azad University, Karaj Branch

Most injury accidents occur on multilane highways because of unsafe lanechange manoeuvers by vehicles. In this paper, required deceleration relations andrelation between highway density values and lane changing duration for one ofthe arterial urban highways of Tehran were evaluated. Analysis results of lanechange trajectories of real traffic flows were shown that most drivers have hadaggressive behaviors. Also, real scale field studies have shown here themaximum value of required deceleration must be 4 m/s2 or less. Based ontrajectory data sets, most drivers remained in stop-go traffic are shown to haveaggressive behaviors. The duration of appropriate lane change in high densitysituations reached 8 seconds while this value is near to 2.5 seconds for free flowwith maximum speed. Most patterns must consider driving behaviorsspecifications for lane changing maneuvers to be effective for collision

Lane Change, Required Deceleration, Collision, Headway