The project location is one of the busiest signalized junctions in the city with persistent traffic delays, and there were proposals by politicians to re-build it into a roundabout. The city wanted to make an informed decision about the improvement of this intersection that will allow to reduce congestion and increase transport capacity without compromising traffic safety for all road users and accessibility. The purpose of the assignment is to assess the transport impact of a proposed self-regulating (roundabout) intersection design, an improved roundabout design and an improved signalized intersection, with application of transport modeling software. 

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Project objectives: 

• Transport impact assessment of a proposed roundabout design, with micromodeling software 

• Development an improved version of roundabout design  

• Development of preliminary design of improved signalized intersection  

• Transport impact assessment of two new design options, with micromodeling software, and comparative analysis of them against each other, the existing situation and the existing roundabout concept (in total 4 scenarios) 

• Conclusions and recommendations for the city. 

 

Project activities: 

• Field survey, desk research, creation of a baseline model in Eclipse SUMO software 

• Road safety and transport assessment of proposed roundabout design 

• Development of drawing scale 1:500 of an improved roundabout 

• Development of drawing scale 1:500 of an improved signalized intersection 

• Modelling of 4 scenarios with different traffic volumes in in Eclipse SUMO software 

• Preparation of a project’s Final report with recommendations 

Project results: 

• The proposed roundabout design received negative assessment due to negative road safety impact and reduced accessibility  

• Modelling indicated that the proposed roundabout design will have drastically lower capacity compared to existing situation because of high pedestrian flows on zebra crossings that will jam the exiting traffic and will be blocking the roundabout 

• An improved turbo-roundabout design will have slightly better performance but still far from matching the existing demand 

• Optimized signalized intersection design allows to make the intersection are much smaller (reduction from 4030 sq.m to 1260 sq.m) that drastically reduces the distance between stop lines, requires less time for traffic and pedestrian to cross the junction, requires shorter clearance time for signal time plan 

• Modelling indicated that the improved signalized intersection design outperforms the existing design by 17%, 28% and 30% at the three busiest entrances 

• The improved signalized intersection design provides for better safety performance, better security, shorter distances for cyclists and pedestrians and therefore encourages non-motorized mobility 

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More information in the report published here

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