Modelling uncertainty in the sustainability of Intelligent Transport Systems for highways using probabilistic data fusion

Abstract

The implementation of ITS to increase the efficiency of saturated highways has become increasingly prevalent. It is a high level objective for many international governments and operators that highways should be managed in a way that is both sustainable i.e. environmental, social and economically sound and supportive of a Low-Carbon-Energy Future. Some clarity is therefore needed to understand how Intelligent Transport Systems perform within the constraints of that objective. The paper describes the development of performance criteria that reflect the contributions of Information Communication Technology (ICT) emissions, vehicle emissions and the embedded carbon within the physical transport infrastructure that typically comprises one type of Intelligent Transport System i.e. Active Traffic Managementa scheme that is used to reduce inter-urban congestion. The performance criteria form part of a new framework methodology 'EnvFUSION' (Environmental Fusion for ITS) outlined here. This is illustrated using a case study where environmental performance and pollution baselines (collected from independent experts, academic, governmental sources and suppliers) are processed using an attributional Lifecycle Assessment tool. The tool assesses the production and operational processes of the physical infrastructure of Active Traffic Management using inputs from the 'Ecoinvent' database. The ICT component (responsible for data links) is assessed using direct observation, whilst vehicle emissions are estimated using data from a National Atmospheric Emissions Laboratory. Analytical Hierarchy Process and Dempster-Shafer theory are used to create a prioritised performance hierarchy: the Intelligent Transport Sustainability Index, which includes weighted criteria based on stakeholder expertise. A synthesis of the individual criteria is then used to reflect the overall performance of the Active Traffic Management scheme in terms of sustainability (low-carbon-energy and socio-economic) objectives.

Sustainability assessment approaches for intelligent transport systems: the state of the art

“…Uncertainty needs to be managed by an appropriate method as ITS systems span multiple locations (i.e., the road-side and datacenter of the traffic control centre). Whilst the selection of methods adopted here have been tested in Kolosz et al [78] and Kolosz [41], they are just one feasible combination. It is therefore important to note that the goal of the review was to highlight ongoing research in ITS appraisal, to stimulate debate in the authors selection of methods and to support the development of an official ITS framework as the technologies become more commonplace.…”

“…Data methods based upon Bayesian subjective probability include Dempster-Shafer theory (DST), which allows evidence to be combined from multiple sources with missing data to give a decision. Kolosz et al [78] combined DST with AHP to estimate the sustainability performance of Active Traffic Management. The main strengths of this approach lie in its ability to treat heterogeneous, uncertain and incomplete data originating from multiple information sources.…”

“…One exception is Kolosz et al [78,79] who integrated LCA and MCA with a probabilistic data method (Dempster-Shafer). The results indicated that datacenter emissions required significant improvement to ensure the ITS lifecycle was sustainable.…”

“…In addition, although certain metrics are available to estimate hardware efficiency, most systems perform multiple operations which make it difficult to separate the energy requirements of ITS and standard day-to-day tasks. Instead, it may be more useful to develop general criteria which reflect the operational performance of the ICT data links using readily available metrics [78] It appears that estimating ICT emissions at the product level is still within its infancy for ITS appraisal, As ITS combines ICT and transport related concepts, it seems advisable to articulate the process around quantitative and non-monetary data values. Overall, the Lifecycle assessment offers a very promising method for estimating emissions throughout the various stages of ITS schemes.…”

Modeling and evaluating the sustainability of smart solutions

“…Every proposed application of smart technologies has to be assessed for its implications for sustainability. There are only few examples of studies that have been devoted to assessing the sustainability of a particular smart solution so far, such as a study on intelligent transport systems (Kolosz et al, 2013).…”