ReFleX aims at characterizing in a comprehensive manner the topological features of large-scale urban vehicular networks built on top of DSRC-based V2V and V2I communication technologies. To that end, the project adopts a multidisciplinary approach, bringing together tools from vehicular networking, wireless communications, transportation theory, and complex network science.

The study will unveil the (yet largely unknown) vehicular network connectivity properties induced by a pervasive adoption of DSRC technolgies in urban environments. That way, ReFleX will evidence the strengths, weaknesses and overall capabilities of large-scale V2V/V2I communication systems, including their actual availability and reliability.

In turn, the understanding of the basic features of the vehicular network topology will allow testing current protocols and architectures intended for DSRC-based networks, by verifying their fitness to the connectivity dynamics of large-scale urban vehicular networks. ReFleX will then take an original bottom-up approach to protocol desgin that puts the network connectivity at the core of the process, and it will propose enhancements and novel network solutions that adapt to the actual features of the network topology.

ReFleX is funded by the Career Integration Grant scheme of the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme. The project started on April 2014 and is deemed to conclude in March 2018.

Host institution

CNR-IEIIT — Institute of Electronics, Computer and Telecommunication Engineering (IEIIT) of the National Research Council (CNR) of Italy 


Marco Fiore — Scientist in Charge 
Christian Glacet — Postdoctoral fellow, now at Université de Bordeaux, France 
Marco Gramaglia — Postdoctoral fellow, now at IMDEA Networks, Spain 

External collaborators

Luca Bedogni — Università di Bologna, Italy 
María Calderón — Universidad Carlos III de Madrid, Spain 
Jérôme Härri — EURECOM, France 
George Jacobs — National Institute of Technology at Tiruchirappalli, India 
Diala Naboulsi — INSA Lyon / Inria Urbanet, France 
Razvan Stanica — INSA Lyon / Inria Urbanet, France 
Oscar Trullols-Cruces — Universitat Politecnica de Catalunya, Spain 
Sandesh Uppoor — Orange Labs, France 
Andrea Vesco — ISMB, Italy 


  • D. Naboulsi, M. Fiore,
    Characterizing the Instantaneous Connectivity of Large-scale Urban Vehicular Networks,
    IEEE Transactions on Mobile Computing, to appear |
  • M. Fiore, A. Nordio, C.-F. Chiasserini,
    Driving Factors Toward Accurate Mobile Opportunistic Sensing in Urban Environments,
    IEEE Transactions on Mobile Computing, to appear |
  • V. Caiati, L. Bedogni, L. Bononi, F. Ferrero, M. Fiore, A. Vesco
    Estimating Urban Mobility with Open Data: A Case Study in Bologna,
    IEEE ISC2 2016, Trento, Italy, September 2016 |
  • M. Gramaglia, O. Trullols-Cruces, D. Naboulsi, M. Fiore, M. Calderon,
    Mobility and connectivity in highway vehicular networks: a case study in Madrid,
    Elsevier Computer Communications, Vol.78, No.15, March 2016 |
  • L. Bedogni, M. Gramaglia, A. Vesco, M. Fiore, J. Härri, F. Ferrero,
    The Bologna Ringway dataset: improving road network conversion in SUMO and validating urban mobility via navigation services,
    IEEE Transactions on Vehicular Technology, Vol.64, No.12, December 2015 |
  • C. Glacet, M. Fiore, M. Gramaglia,
    Temporal Connectivity of Vehicular Networks: The Power of Store-Carry-and-Forward,
    IEEE VNC 2015 , Kyoto, Japan, December 2015 |
  • M. Gramaglia, M. Fiore,
    On the Level of Detail of Synthetic Highway Traffic Required for Vehicular Networking Studies,
    IEEE VNC 2015 , Kyoto, Japan, December 2015 |
  • O. Trullols-Cruces, M. Fiore, J.M. Barcelo-Ordinas,
    Worm Epidemics in Vehicular Networks,
    IEEE Transactions on Mobile Computing, Vol.14, No.10, October 2015 |
  • S. Uppoor, M. Fiore
    Characterizing pervasive vehicular access to the cellular RAN infrastructure: an urban case study,
    IEEE Transactions on Vehicular Technology, Vol.64, No.6, June 2015 |
  • P. Manzoni, M. Fiore, S. Uppoor, F.J. Martinez Dominguez, C.T. Calafate, J.C. Cano,
    Mobility Models,
    Vehicular ad hoc Networks: Standards, Solutions, and Research,
    C. Campolo, A. Molinaro, R. Scopigno (Editors), Springer, 2015
  • M. Gramaglia, M. Fiore, M. Calderon,
    Measurement-based modeling of inter-arrivals for the simulation of highway vehicular networks,
    IEEE Communication Letters, Vol.18, No.12, December 2014 |
  • M. Gramaglia, O. Trullols-Cruces, D. Naboulsi, M. Fiore, M. Calderon
    Vehicular Networks on Two Madrid Highways,
    IEEE SECON 2014, Singapore, July 2014 |
  • S. Ancona, R. Stanica, M. Fiore,
    Performance Boundaries of Massive Floating Car Data Offloading,
    Invited paper, WONS 2014, Obergurgl, Austria, April 2014 |


  • M. Fiore,
    Vehicular networking: from fundamental properties to network solutions
    Habilitation à diriger des recherches, INSA Lyon / Université Lyon I, July 2014 |


  • ReFleX deliverable no.1
    D1 – Mobility and RF signal propagation datasets,
    30/10/2015 |
  • ReFleX deliverable no.2
    D2 – Intermediate results on vehicular network topology characterization,
    31/03/2016 |


Among other objectives, ReFleX is committed to the generation and collection of synthetic datasets of vehicular mobility for network simulation. Below, we provide a list of links to repositories where such open-access datasets, either generated within this project or by other initiatives, can be retrieved.

1. Cologne, Germany
Synthetic dataset of the vehicular mobility in the 400-km2 conurbation of Cologne, Germany. The available dataset describes traffic covering a 2-hour timespan (6 am to 8 am) of a typical weekday 

2. Madrid, Spain
Synthetic datasets of the unidirectional vehicular mobility along three highways (M30, A6 and M40) around Madrid, Spain. The M30 dataset describes 24 hours of traffic during a typical weekday, whereas the A6 and M30 datasets reproduce 30 minutes of traffic during two hour periods (8.30 am to 9 am, and 11.30 am to 12 am) in four working days of a typical week 

3. Canton of Zurich, Germany
Synthetic dataset of the vehicular mobility in the whole Canton of Zurich, Germany. The dataset describes traffic during two 3-hour time intervals (approximately, 6 am to 9 am, and 3 pm to 6 pm) during a typical weekday 

4. Luxembourg country
Synthetic dataset of the vehicular mobility in the whole Country of Luxembourg, a 2200-km2 area. The dataset contains over 110,000 individual trips describing inbound traffic during the first 11 hours of a typical weekday 

5. I5-S/I880-S highways, CA, USA
Synthetic dataset of the vehicular mobility on the I5-S and I880-S highways in Califiornia, USA. The dataset contains seven different traces, corresponding to diverse road traffic densities. Both SUMO source files and output traces are provided 

6. Andrea Costa and Pasubio areas, Bologna, Italy
Synthetic datasets of the road traffic in suburban areas of Bologna, Italy, between 8 am and 9 am of a typical working day. Data is available as SUMO source files 

7. Europarc roundabout, Creteil, France
Synthetic dataset of the road traffic at the Europarc roundabout in Creteil, France. The roundabout features 6 entrances/exits, 2-3 car lanes, 1 bus lane, 4 lane-changing spots, and 15 traffic lights. The dataset covers two rush-hour periods of two hours each 

8. Luxembourg city
Synthetic dataset of the vehicular mobility in the city Luxembourg, a 156-km2 area comprising 931 km of roads. The dataset describes car and bus traffic during 24 hours, obtained via ACTIVITYGEN 

9. Downtown area, Bologna, Italy
Synthetic dataset of the road traffic in downtown Bologna, Italy, between 8 am and 9 am of a typical working day. The data, based on iTetris travel demand and validated through open-access routing data, is available as SUMO source files 

In addition to ready-to-use datasets, a list of important related initiatives is provided below.

The Next Generation Simulation (NGSIM) program was initiated by the United States Department of Transportation (US DOT) Federal Highway Administration (FHWA) in the early 2000's. The program developed a core of open behavioral algorithms in support of traffic simulation with a primary focus on microscopic modeling, and collected high-quality primary traffic and trajectory data intended to support the research and testing of the new algorithms. The NGSIM program has actively engaged traffic simulation vendors to accelerate the inclusion of advanced or improved algorithms in the commercial models used across the world 
Enhanced vehicle trajectory data from the I80-1 dataset of NGSIM 

b. ITDb
The aim of the International Traffic Database project is to provide traffic data to various groups (researchers, practitioners, public entities) in a format according to their particular needs, ranging from raw measurement data to statistical analysis

The MULTITUDE project (COST Action TU0903), funded by the European Union COST Programme over the period 2009 to 2013, developed, tested and promoted the use of methods and procedures for the calibration and validation of traffic simulation models. The project examined issues such as data availability and quality, as well as the relationship between data accuracy and calibration, as well as developing and testing methodologies suitable for calibration and validation of deterministic as well as stochastic models. Major accomplishments were the definition of a general framework for the management of uncertainty in traffic simulation, the development and application of Global Sensitivity Analysis techniques to traffic simulation, the building of a new simulation platform to benchmark dynamic origin-destination (OD) estimation and prediction algorithms, and the development of a new methodology to reconstruct trajectory data from noisy measurements 

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