• Enhancing roundabouts in Rome

    roundabouts in Rome

TPS: Abacus on 3 roundabouts in Rome


Project title:
Draft of an abacus on roundabouts with the microsimulation models of 3 specific roundabouts, Rome, Italy

Contracting authority:

Roma Servizi Per La Mobilità SRL

Public Authority
: TPS Italia
Project duration:
10/2011 – 09/2014

Project description:
The aim of this study was the generation of an abacus for the preliminary estimation of the level of service of a roundabout, once the global demand level and the external radius of the roundabout circle had been established. Such estimation is meant to define the possible use cases of roundabouts, based on the available space for the structure to be inserted into the urban context and on the general demand level affecting the node.

The study is based on the data provided by Roma Servizi per la Mobilità srl (RSM). Such data derive from a series of traffic counts carried out on three roundabouts, namely: the one in Piazza Azolino Hazon, the one in Piazza Oderico da Pordenone and the intersection between via di Casal Boccone and via Ugo Ojetti.

For each intersection, the traffic flows of a complete week day of October 2012 were recorded by means of a video capture system, and of an automatic image decoder. Once the offer had been calculated by implementing the network graph, the traffic control elements and the demand previously acquired, the intersections were simulated using the microsimulation software PTV Vissim.

For the calibration of the microsimulation models, TPS made use of the images collected during the traffic counts of the vehicle flows.

In addition to the skim indicators provided by PTV Vissim, the Level of Service was calculated using the new software tool PTV Vistro.

Software & modules used: PTV Vissim, PTV Vistro

TPS Transport Planning Service