Research Projects

Real-time hierarchical control and monitoring of urban traffic systems


The introduction of Intelligent Transportation Systems (ITS) technologies and new sensing hardware promise significant progress in reducing the congestion level in cities. With respect to monitoring, reliable and efficient estimation of travel times and other performance measures is still not a wide spread accomplishment on arterials. The issue is not only that the existing monitoring infrastructure in arterials is less dense than freeways but also that arterial systems traffic dynamics are significantly different than these of freeways and fixed sensors cannot always give the required level of information. Thus, the two scientific aspects of (i) monitoring and (ii) controlling congestion in local arterials is the emphasis of the proposed work. This study aims in capitalizing both fixed and mobile sensors. The proposed methodology will provide for efficient estimation of travel time reliability measures. These performance measures will be an important tool to develop and test a different type of control of urban networks, a multi-level hierarchical control. The building block of our methodology is a sub-network with a Macroscopic Fundamental Diagram representation. A research challenge is to partition a network in homogeneous sub-networks with an MFD representation and to build a hierarchical feedback control network of multiple levels which may require different data granularity at each level. Another important aspect of this research is what level of monitoring is required to guarantee “observability” of the state of the system. The validation of the monitoring and control methodologies will be conducted in complex city-level scenarios using advanced micro-simulation software and data from field experiments.
Principal investigator    Nikolas Geroliminis
Project managers   Yuxuan Ji, Mohsen Ramezani, Jack Haddad
Period   Sept. 2010 – Aug. 2013


Movement Conflicts in multi-modal urban traffic systems: Modeling Congestion and developing more sustainable cities


Description: cities around the world grow rapidly and more people and modes compete for limited urban space to travel, there is need to understand how this space is used for transportation and how it can be managed to improve accessibility. Our research seeks to shed some light in the modeling, planning and management of traffic flow for overcrowded cities with multimodal transport. We develop methodologies to model and understand the collective behavior for different types of multimodal systems, with emphasis in conflicts for the same road space (e.g. mixed traffic of buses and cars or vehicles searching for parking). Ultimately, the goal is to develop optimization tools on how to distribute city road space to multiple modes and to understand the level of accessibility for cities of different structures. We also investigate what type of real-time active traffic management schemes (congestion pricing, vehicle restriction, large scale traffic signal control) can improve mobility measures in a city. The accuracy of the developed models will be tested for different routes and different networks using real bus, signal, geometric and traffic data. Also, the models will be tested with a variety of different types of realistic multimodal networks using microsimulation.
Principal investigator    Nikolas Geroliminis
Researchers Involved   Nan Zheng
Period   Jan. 2011 – Jan. 2014


OPTIMUM: Optimized ITS-based Tools for Intelligent Urban Mobility


In this project three leading research teams collaborate with the aims at developing innovative solutions for intelligent urban mobility to address the urban mobility challenges. The collaborating partners have complementary expertise and common vision and interest for ITS research. To achieve aforementioned objectives, the project is designed to harmonise the research program by exchange of information, ideas, resources etc between three strong research institutes in Switzerland, France and Australia. This effective way of learning will enhance the research capabilities of each partner by exchange of researchers with specialised knowledge. This cross-border and cross-disciplinary cooperation will strength the collaboration and mutual understanding and open new possibilities to promote new direction for application of ITS systems. The project addresses its research goals by dividing the research into three research oriented working groups (WG) as follows:
·       Integrated real time traffic information WG focuses on development of methodologies for: a) short-term travel time prediction for different modes and networks; b) travel time variability; and c) real time multimodal travel traveller information and real time routing.
·       Network efficiency and Weather impact modelling WG focuses on the a) optimising the observability of urban traffic system; b) understand and assess the effect of adverse weather conditions on road networks; and d) develop response strategy to mitigate the impacts of weather on road networks.
·       Cooperative traffic management WG focuses on a) Active traffic management algorithms; b) Traffic signal optimization; and d) Traffic simulation modelling for testing and evaluating emerging cooperative systems.
 Principal investigator    Nikolas Geroliminis 
Period   May 2011 – April. 2014


Analysis, evaluation and recommendations for the Nice-Monaco Veolia bus system

Veolia transfers about 1.5M passengers per year in the Nice-Monaco line using 3 different routing options. The majority of the demand is for the southern corridor. This demand consists of workers who live in Nice and work in Monaco, workers who live between Nice and Monaco and a large number of tourists. The tourists choose the Southern corridor because it provides many attractions during their trip. This line operates in a non-efficient way, as there is high level of congestion (a trip of 30min in the off-peak lasts for more than 60min in the peak) and high spatial heterogeneity in demand, which results in out-of-vehicle delays for passengers. The congestion spreads throughout the corridor and also at the entrance roads to Monaco and Nice. This project investigates this complex corridor, identify the causes of congestion and propose alternatives for more efficient transfer of passengers to their destinations. The research involves (i) Temporal and spatial estimation of bus and car travel times for all three alternatives, (ii) Temporal and spatial analysis of demand for buses and (iii) Evaluation of the alternatives. Among the alternatives we plan to investigate (i) separation of the southern route to 2 lines with possibly different stops, (ii) adjustment of the frequencies for the different lines and (iii) possibility of introducing a new line in the Middle corridor.
Principal investigator    Nikolas Geroliminis
Researchers involved  Stefan Binder, Burak Boyaci, Jeanne Ythier
Period   Dec. 2010 – July 2011