Safety Performance Evaluation of the New Mega Elliptical Roundabout Interchanges Using the Surrogate Safety Assessment Model

Mega elliptical roundabouts are considered a new kind of intersection and can be found on rural multilane highways. Their form is that of an elongated ellipse. They combine the best advantages of an unconventional median U-turn intersection and roundabout. The purpose of this research is analyzing safety performance for mega elliptical roundabout interchange using the VISSIM software version 4.30 and the surrogate safety assessment model (SSAM) software version 3. This research also considered eight other interchange designs to compare them with the mega elliptical roundabout interchange. In total, 20 scenarios were analyzed using VISSIM version 4.30 then tested by SSAM software version 3. To compare the different interchanges in terms of the mean values of conflicts, the one-way analyses of variance (ANOVA) were conducted. Based on the research results, a mega elliptical roundabout interchange was one of the best interchanges studied in this research in relation to the frequency of conflicts as a total and the frequency of crossing conflicts.