SMART NETS - Signal Management in Real Time for urban traffic NETworks
Overview
Background & policy context:
The limited availability of space in urban centres prevents the extension of existing infrastructure and, with continuously increasing mobility demands, requires solutions that will alleviate serious congestion problems through the best possible utilisation of existing infrastructure.
This calls for the employment of the most efficient actuated systems that respond automatically to the prevailing traffic conditions so as to avoid oversaturation, increase throughput, and reduce travel times in urban networks. A number of real-time (traffic-responsive) urban control strategies currently exist.
These strategies, however, suffer from two major disadvantages. They do not directly address saturated traffic conditions, and they are functionally decentralised, basing signal-setting decisions for each junction on the current traffic state in adjacent streets only. In addition, several of the currently available strategies require specific real-time measurements, or complex implementation software, limiting their easy transferability and increasing their implementation costs.
Objectives:
SMART NETS aims at enabling a significant improvement of the international state-of-the-art in real-time network-wide urban traffic control via application, demonstration, and comparative evaluation of the new-generation control strategy TUC (Traffic-responsive Urban Control).
TUC employs advanced automatic control methodologies which may lead to improvements in the order of 40% of journey times as compared to fixed-time settings under saturated traffic conditions where all current signal control strategies are known to perform poorly.
Within SMART NETS, TUC will be extended to consider public transport priority measures. The demonstration will be conducted in extended network parts of Southampton, Munich and Chania, and include field-comparisons with the current resident control methods (SCOOT, BALANCE, TASS). A successful completion of SMART NETS would mark a new era in urban traffic control worldwide, with substantial technological and economic impact for European ITS activities.
Methodology:
The first stage in SMART NETS was the design and testing of TUC for the three demonstration sites and the inclusion of public transport priority in TUC.
At this stage extensive simulation investigations were performed under different scenarios, e.g., of demand, incidents and device failures, and based on various criteria, such as average journey time, throughput, saturation levels and fuel consumption. The outcome of this stage was the design of the TUC control law and the preliminary assessment of TUC's capabilities for the three application networks.
This was followed by the field implementation and verification of the strategy in the three test sites. The same generic software was implemented in all sites, with the particular topologies and traffic conditions reflected in corresponding individual input files for each network application. This demonstrates the transferability and easy applicability of TUC.
Finally, and currently underway, are the field demonstrations. Analysis of data collected during demonstration in the three sites will allow the assessment of the impact of TUC in each site, as well as a comparative evaluation of the operation of TUC across all sites.
Evaluation will be performed according to the SMART NETS Evaluation Plan, which was developed at an early stage of the project.
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