Re-design of a road node with 7D BIM: Geometrical, environmental and microsimulation approaches to implement a benefit-cost analysis between alternatives

Congestion and safety at road intersections is a main traffic challenge involving several technicians. This paper focuses on spillback of a three-level intersection in Italy, where five roadways merge. More than 130 conflict points affect the existing roundabout where more than 13,000 vehicles move in the peak hour. In order to improve both capacity and level of service and to reduce delay and emissions due to queue, 4 scenarios have been investigated and designed using the Civil 3D tool. VISSIM 11 simulated their operational performances, while SimaPro allowed assessing carbon footprints. Moreover, construction, maintenance and usage costs have been estimated. The results showed that the best scenario implies new overpasses and underpasses to eliminate crossing conflict points, to reduce merging and diverging ones, and to link directly the busiest arms. This proposed 7D BIM methodology consists of geometrical, environmental, microsimulation approaches to implement a benefit-cost analysis useful for decision makers.