Underground Roundabouts: Analysis of Several Layouts for A Case Study in Urban Area

Marco Guerrieri1, *, Matteo Sartori1
1 Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy

Article Metrics

CrossRef Citations:
Total Statistics:

Full-Text HTML Views: 886
Abstract HTML Views: 347
PDF Downloads: 143
Total Views/Downloads: 1376
Unique Statistics:

Full-Text HTML Views: 462
Abstract HTML Views: 175
PDF Downloads: 101
Total Views/Downloads: 738

Creative Commons License
© 2020 Guerrieri and Sartori

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to the author at the Department of Civil, Environmental and Mechanical Engineering, University of Trento, Italy; Tel: 3339993614; E-mail:



Roundabouts eliminate some of the most complex and dangerous aspects of traditional at-grade road intersections. In recent times, novel two-level roundabout layouts have been proposed (i.e. target-roundabout and four-flyover roundabout). Nevertheless, no research on underground roundabouts is available. This paper analyzed the underground roundabout planned in the city of Trento (Italy).


The paper examines an underground roundabout in an urban context, planned with the purpose of alleviating traffic congestion in the city of Trento (Italy). Four different layouts have been studied.

Methods and Results:

This study was conducted with the help of traffic microsimulation in the AIMSUN environment. The traffic model was calibrated using GEH index. The simulated queues are significantly close to the real queues measured in the year 2020.


Underground roundabout can reduce queues, travel times, fuel consumption, air pollutant emissions etc. This particular type of roundabout could be used in urban contexts with a traffic demand and congestion problems comparable to those of the present study.

Keywords: : Underground roundabout, Right-turn bypass lane, Traffic congestion, Micro simulation, Traffic model, Road intersection.