EfectAPPLICATION OF “EFECT - AN EVALUATION FRAMEWORK OF ENVIRONMENTAL IMPACTS AND COSTS OF...

7/29/2019 EfectAPPLICATION OF EFECT - AN EVALUATION FRAMEWORK OF ENVIRONMENTAL IMPACTS AND COSTS OF TRANS

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EFECT evaluation framework of environmental impacts and

costs of transport initiatives

Dimitrios Tsamboulas *, George Mikroudis

Department of Transportation Planning and Engineering, National Technical University of Athens, 5 Iroon Polytechniou,

15773 Zografou, Athens, Greece

Abstract

EFECT is a generalised methodological framework for evaluating the impacts resulting from trans-

portation projects with a specic orientation to environmental impacts. The innovative aspect of the

methodological framework is the combination of Multi-Criteria Analysis (MCA) with Cost-Benet

Analysis (CBA) methods to come up with an overall assessment of transport initiatives impacts over

dierent geographical regions and time periods. Thus, it addresses both spatial and time impacts of

transportation networks for all modes. The framework comprises four steps: structuring, weighting, rating,

and exploring. Uncertainty is explicitly treated in the framework through fuzzy sets or, indirectly, through

sensitivity testing. EFECT, using an additive function combining MCA and CBA methods, providessimplicity and intuitive understanding of results. This allows the use of either a core approach with a basic

set of criteria and weights, or the application of a more detailed evaluation, when needed. The way EFECT

is applied and the results produced are presented through a case-study example. 2000 Elsevier Science

Ltd. All rights reserved.

Keywords: Transport investments; Environmental impacts; Multi-criteria analysis; Evaluation of transport projects;

Uncertainty in evaluation

1. Introduction

Evaluation (ex-post or ex-ante) of transportation plans, initiatives and projects have beencarried out in the past, using a variety of methodological frameworks. In terms of content, theavailable methodologies can be classied into Cost-Benet Analysis (CBA) (Abelson, 1979;

Transportation Research Part D 5 (2000) 283303

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* Corresponding author. Tel.: +301-7721367; fax: +301-7721327.

E-mail address: [email protected] (D. Tsamboulas).

1361-9209/00/$ - see front matter

2000 Elsevier Science Ltd. All rights reserved.P I I : S1361- 9209( 99) 00038- 3


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Freeman, 1979; Danning and MacKnight, 1990), Multi-Criteria Analysis (MCA), (Nijkamp and

Blaas, 1993), Social-based Analysis (Tsamboulas and Mikroudis, 1996; Verhoef, 1994), Decision-Analysis, other specic type-applications (land suitability analysis, rapid assessment methods,

resource management approaches) and simulation/mathematical modeling (Nickols and Heyman,1982; Roson and Small, 1998). In terms of typology, they all use variations of checklists, matrices,networks and overlay methods. In all cases, one of the key objectives is the inclusion of envi-ronmental quality/impacts considerations in planning and decision-making. Recently, there is

research relating the environment impact assessments to policy considerations (Banister andButton, 1993; Button, 1993; Banister, 1998).

At European level, it has been recognized that Environmental Assessment (especially at the

strategic level bearing the generic name Strategic Environmental Assessment (SEA)) should bedeveloped as an integral part of the decision-making process for policies, plans and programmes

(EC, 1993, 1996). The same importance is given in USA with the creation of EnvironmentProtection Agency (EPA). Especially for the planning or implementation of transportation

projects, environmental appraisals start with an identication of possible impacts to variousaspects of the natural and social environment, and result either in some form of tabular rep-resentation of impacts or in an aggregate scoring of alternatives. The last part requires con-

verting environmental eects into monetary or non-monetary values, a task with seriousmethodological and philosophical diculties. The nal balancing of values and ranking of al-ternatives is either included in the method or left to the decision-maker (DM). The `easy' part of

an environmental evaluation is the analytical one, being the identication of the impacts. The`hard' part is the evaluation of each impact and the synthesis of the results in order to facilitatedecision-making.

The diculties in arriving at a generalized framework for environmental evaluation are both

procedural and conceptual. In operational terms, such framework should be easy to be under-stood and employed by DMs, while meeting a series of eciency criteria, such as generality,independence, reliability, exibility, few data needs, etc. On the other hand the evaluation

framework should be philosophically coherent, able to deal with challenging issues, such as un-certainty, time frame, network eects, modal changes, while integrating cost and judgement valuesinto the evaluation.

This paper presents a generic methodological framework, called Evaluation Framework ofEnvironmental impacts and Costs of Transport (EFECT) initiatives. Its scope is ratherbroad since it aims to cover all kinds of transport environmental initiatives, namely policies,plans and projects, either for small-scale (local) or large-scale (regional/national) assess-

ments.In order to make a more simple presentation the method is focusing on environmental impacts.

However, the same principles and structure can be applied to evaluate other type of impacts aswell.

The requirements for such a generic methodology are presented in the following section. Next,the detailed framework is formulated and the procedure used in applying the methodology areexplained. Then, a way to handle uncertainty is provided, as well as the manner to deal with the

time dimension of environmental evaluation. Finally, a case-study of EFECT application in theevaluation of alternative road design schemes is presented, which demonstrates the advantages ofthe methodological framework, when used in a GIS environment.

284 D. Tsamboulas, G. Mikroudis / Transportation Research Part D 5 (2000) 283303


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2. Requirements for the evaluation methodology

2.1. General requirements

The basic requirements for the development of a generic methodological framework for en-vironmental evaluation of transport infrastructure projects are the following: combine environmental eects with monetary values,

follow a network approach for the spatial variation of impacts, consider variation of impacts over time, handle uncertainty,

be practical and understandable.The above requirements lead to certain fundamental choices in the mathematical structures that

are part of the framework. Thus, one basic choice is to employ an additive function for the ag-gregation of individual values into a single score. This allows for an easy and robust combination

of MCA with CBA (Tsamboulas, 1998), and it facilitates application to networks on dierentregions in space and at dierent periods of time. It also makes the method more practical andeasier to be understood by the DM, and eventually, more defendable.

2.2. Practical and methodological issues

End-users of the framework can be DMs. They might be either individuals such as transportplanners and designers or public entities (European, national, local) with institutional, adminis-

trative interests.The methodological framework could be applied both to urban and inter-urban projects, re-

gardless of transport mode, as well as to the development of terminals. On the physical scale, it isappropriate for projects referring to a section (e.g., 10 km), a corridor, or a network. In addition,

the project can be extended over several regions in dierent areas or countries. Alternatives can beconsidered both at scheme (conception) level and at project level. Moreover, the methodologyhandles environmental impacts at any level of detail in the natural and social environment. Lastly,

all of the above could be handled in a time framework and provisions are made to deal withuncertainties.

2.3. Overall characteristics of the methodology

Based on the above requirements the main characteristics of EFECT are the following: the use of a hierarchical approach,

the utilisation of an additive multi-criteria model, the combined use of MCA and CBA methods, the use of weights for criteria and spatial aggregation of impacts,

the inclusion of uncertainty at all stages of the evaluation, the explicit handling of the time dimension of impacts.

For practical reasons a core method is used. For a more detailed evaluation, the treatment ofuncertainty and dynamic time eects can easily be added to.

D. Tsamboulas, G. Mikroudis / Transportation Research Part D 5 (2000) 283303 285


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3. Methodological framework

3.1. Overview

EFECT comprises four steps: 1

1. Structuring: Constructing a decision-tree from the environmental and monetary factors of theproblem:

(a) Objectives: Dening basic goal and/or objective(s).(b) Criteria: Describing the appraisal parameters and their corresponding index functions.(c) Hierarchy: Dening how the criteria are related hierarchically to the problem objectives.

2. Weighting: Dening how the criteria, geographical regions and time horizons are weightedagainst each other in the evaluation:

(a) criteria weights,(b) regional weights,

(c) time weights.3. Rating of the alternative projects:

(a) applying the criteria, weights and structure to evaluate and rank the alternative projects,

(b) combining MCA with CBA results.4. Exploring the results:

(a) performing sensitivity analysis on the criteria, weights and values in order to explore pos-

sible variations of end results,(b) using fuzzy sets to incorporate uncertainty in the evaluation,(c) considering the evolution of (1) and (2) of the above, over time.

In a given decision situation, alternative transport projects can be evaluated following the above

four steps and by receiving `scores' corresponding to the environmental criteria employed by themethodology. For scoring, either a `quality index' can be used, where higher scores indicate betterquality for the environment, or on the contrary, an ìmpact/pollution index' can be used, where

higher scores mean higher impacts or levels of pollution, thus lower environmental quality.The rst three steps comprise a `core' method, which can be applied in the majority of cases.

When, a more detailed evaluation is needed the last step (3) is followed, with the inclusion of

additional procedures for handling uncertainty and time dimension.

3.2. First step structuring

It denes a decision-tree, comprising the environmental and monetary issues consisting of (a)the objectives, (b) the evaluation criteria and (c) how the criteria are combined to meet the ob-jectives.

The òbjectives' usually require specifying the goal and the options of the evaluation. Suchoptions can be alternative policies, plans, or projects that extend over a certain geographicalregion (space) and a period of time. Thus, alternative òption', `space', and `time' combinations

1 The original idea of the four steps was developed within the EUNET project, referring to all types of impacts

(Beuthe et al., 1998).



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can be dened. The main goal of the evaluation is either to rank the options directly through

MCA, or to rate the options for further combination with cost data or CBA results. In addition,variation of options over space allows the user to follow a network approach: projects can be

broken down to nodes and links and evaluated according to the geographical regions they arelocated in. On the other hand, variation of options over time allows the inclusion of time relateddynamic eects.

Depending on the objectives, a dierent set of `Criteria' may be used. The term criterion is used

instead of the more common term indicator, since the criteria are the elements forming a decision,and each criterion requires one or more indicators for its description. The evaluation and rankingof alternative transport options requires the construction of a hierarchy of several sub-criteria

which when combined together produce the score of a given option, according to the super-cri-terion they are related to in the hierarchy. In this manner, any number of criteria groupings, which

in turn are grouped into other super-criteria can be formed.In EFECT, the user, according to his/her objectives (Tsamboulas and Mikroudis, 1999) can

dene the form of the hierarchy. An initial set of environmental factors that can be used asframework variants in the hierarchy includes impacts to the natural and the anthropogenic en-vironment from the construction and operation of transport projects of all modes: land (road/

rail), ports for maritime transport and airports for air transport (Mikroudis, 1996). The formu-lation of these environmental factors into a decision-tree is shown in Fig. 1.

The underlying mathematic structure of the model (additive function) allows for maximum

exibility in the selection (or even addition) of criteria (and subsequent indicators) that the DMwants to include in the evaluation. Since weights are calculated for the selected criteria andnormalized at the end, the nal score represents the overall assessment for the set of weights

selected by the DM.

In forming the decision tree, balance is kept between CBA and MCA methods by keeping theircomponents separate all the way to the end, until making the nal decision. A two-stage approachis adopted comprising:

Fig. 1. Proposed structure of decision-tree.



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(a) a pre-screening stage using CBA and a budgetary threshold;(b) an evaluation stage using a MCA method, where CBA output(s) is (are) one of the main

criteria used in the decision.

Note that, by keeping CBA and MCA results separate CBA results can be converted to a commonscale in order to come up with a total score for MCA. Other options consider: MCA results as

benets, using an environmental quality index, so they can be combined with costs; separatemonetary and non monetary terms, without converting one to the other, leaving the DMs tobalance the two at the end.

In constructing such a decision tree, the following are important: Criteria should be able to cope with dierent modes, countries and types of investments (pri-

vate/public or both). If necessary, non-technical criteria, such as political and/or ethical shouldbe used.

The level of aggregation of impacts, at which the approach is typically required to work shouldalso be taken into account, with the possible introduction of sub-criteria, such as `public accep-tance'. Such sub-criteria should assume a non-zero weight only when further disaggregation is

necessary.Care to avoid double counting within both the CBA and MCA components of the tool and

between the CBA and MCA components. Impacts such as employment or accessibility almost

inevitably will double-count with standard CBA impacts in ways entirely impossible to disen-tangle. The best proposed compromises seem to be: to introduce criteria (especially environmental ones), being as orthogonal as possible to impacts

recorded within the CBA, to measure the MCA criteria to represent only contributions (generally towards strategic

goals), which are over and above those recorded as direct project impacts.

An important feature of the EFECT is the capability to turn on or o, any given criterion, orcombination of option-spatial region or option-time dimension. Only `active' criteria that are

related to space and time options are used in the evaluation. In the second step of the evaluationcriteria weights are normalized based on the active options, space weights are normalized based

on the active options-space combinations, and time weights are normalized based on the activeoptions-time combinations. This means that certain criteria can be considered `inactive' either forthe purposes of the evaluation, or for a given region and period of time. This allows for changes in

basic features of the project, plan, or policy over space and time, which simply may not exist or beirrelevant in dierent geographical regions or periods of time. The capability of the methodologyfor the creation of some inactive criteria could be used to develop a simpler evaluation meth-

odology, if there is data availability problems or time constraints.

3.3. Second step weighting

A novel aspect of EFECT is that it incorporates the spatial variation of impacts by introducinga network approach. This means that evaluation of transport infrastructures is not limited to asingle project or corridor but it can encompass an entire network extending over many dierentregions or even countries. Lastly, impacts extending over dierent periods in time (e.g., envi-

ronmental ones) as well as combination of changes over space and time are handled by themethod. To accomplish this, EFECT employs three sets of weights:



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(a) criteria related weights,(b) regional (spatial) weights,

(c) time weights.

To determine the weights, one or a combination of the following methods can be used:1. direct specication by the DMs,

2. specication by a panel of experts, (e.g., Delphi technique),3. by pair-wise comparisons (Yager, 1977; Saaty, 1980).For the measurement of criteria-related weights, EFECT employs the pair-wise comparison,

which is the most ecient weighting method, well-established, with a good record of practicality,operational eciency and reliability, as well as acceptance by the DM (in terms of being short,

easy to understand).The underlying principle is to establish relative impact weights and also, impact scores if re-

quired, using pair-wise comparison of the judged importance of impacts (or relative levels ofimpact). A concern over using this approach for score estimation is that the relative scoresachieved are strongly inuenced by the particular set of alternatives considered. Therefore, if at a

later stage other transport projects are added, there could be rank reversals, particularly if theyhave more extreme scores. This is the main reason behind the use of pair-wise comparisons forweight estimation in the proposed methodology.

Pair-wise comparisons become impractical when the number of criteria is large, usually morethan 10. Thus, it is advisable to keep the number of criteria limited, or to group criteria togetherand apply the method within and among groups of criteria. For the determination of regional

weights, EFECT applies a direct specication either by the DMs or by an expert panel.Regional weights are used in EFECT to incorporate into the evaluation the relative impor-

tance of dierent regions traversed aected by the transport infrastructure. To accomplish it,

EFECT requires a subdivision of the specic project into segments as it traverses dierent re-gions.

Alternatively, a network approach can be used, considering separate regions that correspond tothe various segments of a transport network, and consequently they can be assigned to both nodes

and links of the specic network. However, dierent weighting must be used for the two com-ponents of the network since the links are longer and traverse larger geographical areas and thenodes may conceptually represent entire cities or other anthropogenic activities (e.g., terminals).

Likewise, when comparing projects crossing two dierent geographical regions, all project seg-ments in one region and all project segments in the other region need to be considered and theirresults should be combined (see Fig. 2).

Before proceeding to the evaluation, once the dierent regions are dened, dierent sets ofcriteria weights need to be established within each region. Each of these criteria weights is gen-erally determined through pair-wise comparisons.

The regional weights can be determined through direct specication by experts. Nevertheless,for a small number of criteria and regions, pair-wise comparisons may be employed to determine

the weights for all criteria simultaneously.As an example to illustrate these applications, two regions a and b and two projects are con-

sidered: (I) an airport project in region a, (II) a motorway project in region b. Three super-criteriaC1, C2, C3 are employed (e.g., C1 social impacts, C2 environmental impacts, C3 constructioncost). The weights are determined with the following alternative approaches:



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(i) By separate pair-wise comparison: For region a determine criteria weights C1a, C2a, C3a (3comparisons) and for region b determine criteria weights C1b, C2b, C3b (3 comparisons). The

criteria determine the relative importance of construction costs, social and environmental im-pacts in regions a and b. Initially the regional weights Wa and Wb (1 pair-wise comparison) arespecied. They determine the relative importance for the DM of regions a and b, respectively.

The combined regional-criteria weights are W1a Wa W3b Wb.(ii) By combined pair-wise comparisons: For the two regions the combined regional-criteriaweights W1a, W2a, W3a, W1b, W2b and W3b (15 comparisons) are specied. This option allows

the modication of the weights obtained, by further multiplying them with the regional weightsWa and Wb to account for the relative importance of regions a and b, in addition to the oneconsidered in criteria C1, C2, C3.

The DM can consider the weights obtained according to option (i) as a sucient approximationof those obtained according to option (ii). It is evident that the second option, even for a rea-

sonably small number of criteria (e.g., 10) and regions, (e.g., 5), is practically impossible, requiringthe DM to carry out 1225 comparisons.

In the case of the evaluation of the new project (III) evaluation crossing regions a and b (e.g., arailway line), EFECT requires the project to be divided into two segments: segment a for region aand segment b for region b. EFECT employs the weights as dened with the two separate projects

I and II for the respective regions: W1a, W2a, W3a and W1b, W2b, W3b. It is interesting to note thatweights W1a, W2a, W3a are the same for both projects (I) and (III-segment a) of region a, as wellas the weights W1b, W2b, W3b are the same for both projects (II) and (III-segment b) of region b.

As for the regional weights, Wa is applied to all projects in region a, and Wb to all projects inregion b.

Lastly, a third set of weights can be handled by EFECT to consider the time dimension. En-

vironmental impacts can be considered as immediate (during construction), short-term (during therst years of operation) and long-term. Weights with same or dierent values can be applied,depending on the length of time or other considerations.

The three types of weights are normalized and then multiplied to obtain an overall weight forthe three dimensions of the evaluation: criteria, space, and time. Normalization takes place by

using only the àctive' criteria, the combinations of òptions over space', and the combinations ofòptions over time'.

Fig. 2. Schematic representation of regional and corresponding criteria-related weights.



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3.4. Third step rating of the alternative projects

The third step requires the integration of steps 1 and 2 for the selection of the optimal

project option among competing alternative ones. At this stage, the methodology consists of acore evaluation method with a series of alternative or additional procedures, which can enhancethe core process. The core approach is relatively straightforward and uncontroversial. A seriesof optional enhancements and/or supplementary procedures are added, which represent im-

portant innovative steps in the environmental evaluation methodologies, the most importantbeing: Fuzzy evaluation: An alternative way to represent impacts as fuzzy quantities instead of crisp

numbers, with associated membership functions. This allows for the treatment of uncertaintiesboth in values and weights used in the assessment.

Time-dependant evaluation: `Snap-shots' taken at dierent time-horizons, for example: currentsituation, end of construction period, end of project life (e.g. 30 years). Each snap-shot may

require a re-denition of criteria-weights-regions before evaluating the alternatives. Employingtime integration functions corresponding to each criterion for the specied time intervals canmeasure the environmental impacts and the accumulated costs over time. This is an extension

of the decision-making tree into a third dimension, time.Thus, EFECT is designed in a modular fashion allowing the utilisation of either the core meth-odology or the enhancements to the core method as presented above and possible future meth-

odological additions.The core method follows the conventional framework of MCA. The impacts of CBA expressed

in money values can be converted into the MCA by EFECT. Thus `cost' can simply be considered

as an additional criterion in the MCA part. Environmental benets, if any, is incorporated

through the `quality index' derived by MCA, whereas a `pollution index' is assigned to costs.The evaluation model in EFECT is expressed as:

RankAiYOC1Y F F F YCnc for i 1Y npY 1

where Ai are the np transport options under the aggregation function O(Cij) dened over the nc

criteria using the scores Cij.

The additive function chosen by EFECT, being a simple aggregation function and easy tounderstand. However, it may exhibit the following problem: while at least one score is of for-bidding low quality, the overall score may not present low quality and vice versa (due to com-

pensation between the criteria). On the contrary, the product functions do not exhibit thisproblem, but they are more dicult to understand since they are highly non-linear. A combi-

nation of all types of functions is possible. The aggregation for the combination of options, spaceand time function is used in EFECT in the following form:

Oi

jncY knrY lntJYKYl1

Wji Wki Wli CjXij 2

or alternatively for fuzzy applications:

Oi

jncj1

Wjk CjXijY 3



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Si knrk1

Wik oiY 4

Ti lntl1

Wli Sli

ttetto

flit dtY 5

where Oi or oi are the aggregation functions of a given segment of option ifor all criteria cj, Si theaggregation functions of option i, for all its segments k in dierent regions, Ti the aggregation

function of a option i, over the time interval from t to to t te, wjk the criteria weights foroption iin region kand time l, wki the regional weights for option i, wli the time weights for optioni, fli(t) the growth function for Si, the region in consideration (for a discrete function, the

is

replaced by R), nc the number of criteria, nr the number of geographical regions crossed by projecti, and nt is the number of time periods for evaluating the impacts, for project i.

The core approach comprises Eq. (2) which replaces Eqs. (3)(5) using crisp numbers. The

treatment of space (Eq. (4)), and the treatment of time (Eq. (5)) are optional to the core approach.Eq. (2), when wki wli 1 it is reduced to the classic case of MCA with just a set of criteria thatdo not change over space or time. The treatment of uncertainty (presented in Section 4) using

fuzzy numbers is an enhancement to the core approach that can be used for a more detailedevaluation of impacts.

The above presented model used in EFECT is additive in function, linear in the weights wjand physical parameters xij of the criteria, but potentially non-linear in some or all of the

criteria scores cj and the growth functions fij. To measure the performance of the specic projectwith respect to the chosen criteria, measurement methods are chosen to produce values, which

are at least ordinal and, ideally, in interval/ratio scale measures. If the latter is not possible, away for the values to be converted is introduced. Verbal assessments should be avoided exceptwhen used as a purely supplementary qualication to the formal evaluation model. Wherejudgements are required, they need to be translated to a common scale with associated verbal

descriptions of typical situations corresponding to some or all of the scale gradations. To thisend, optionally, the fuzzy model can provide for conversions of verbal expressions to numericalvalues.

Score levels may be estimated either directly/judgmentally, or by using a simple transformationgraph spanning over all plausible values, usually for criteria which have some direct interval/ratioscale measurement. On the grounds of simplicity, it is recommended that this graph is linear, but it

can also be non-linear when needed.The values converted to a scale or scores are measured independently of weights. Scores are

proposed to be on a 0 to 1 scale, where 0 is the lowest feasible and 1 is the highest feasible level tobe attained by the specic criterion. The scale could be increasing or decreasing, depending on the

objectives of the evaluation.Finally, for the evaluation and ranking of the alternatives each alternative gets an overall score

as derived from the function (1) and thus, the projects under evaluation are ranked rst, second,third and so on.

To be complete, the core approach should be used with a `default' set of criteria (e.g., those ofFig. 1). Thus, several evaluations performed over dierent regions or dierent time periods could



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easily be compared. Also, based on the standard set of criteria, reference could be made to

`standard' characterizations of environmental quality, such as `good', `average', `poor', etc.The core approach, apart from being a reasonably common form of aggregation within the

multi-criteria literature, is also consistent with the idea that the relative inuence of dierentdimensions of impact should be constant and predictable. Moreover, it is broadly transparent tousers and, as the specic impact level changes, it is consistent with the intuitive notion of non-linear `returns' to some impacts. The spatial evaluation (Eq. (3)), time-frame evaluation (Eq. (4))

and handling of uncertainty using fuzzy numbers are add-ons to the core approach, for moredetailed evaluations. In addition, the option to measure the criteria performance in monetaryvalues is a standard option of EFECT.

The use of a non-linear or a step-wise growth function allows to assess the accumulation ofimpacts over time considering that certain impacts (e.g., land take) may remain constant over

time, whereas others may have an exponential growth (e.g., pollution levels) or follow some othertype of growth (e.g., noise levels). The consistent use of an additive function over all regions,

project segments, criteria, and time periods of evaluation allows to compare dierent projects indierent regions and at dierent time horizons.

3.5. Fourth step exploring the results

Although this step is optional, it constitutes an essential part of the decision-making. It may

comprise any one of the following options:(a) sensitivity analysis,

(b) treatment of uncertainty through fuzzy sets,(c) evaluation over time.

The rst option, sensitivity analysis, is achieved through a software implementation of EFECT asan electronic database of criteria, regions and time frames. This software has been applied to thepresented case study, dealing with the application of EFECT.

In order to explore the relative performance of projects when underlying assumptions change,

the method allows users to exchange one set of impacts and regional or time weights for anotherset. This could involve user-specied changes in specic weights or, allow the opportunity for theuser to be able to derive his/her own weight set, if this has to do with MCA impacts. Evidently, in

MCA it is necessary to re-scale weights if any is changed. In EFECT the software model does itautomatically, as well as other necessary calculations, e.g., calculation of eigenvectors, aggrega-tion, ranking, etc.

Since the user is allowed to add/delete criteria within the MCA, the model allows each time todirectly specify or derive the weights using pair-wise comparisons. For data base purposes, the

original assessment is retained with the initial weights and original score estimates to provide thebasic default projects scores and rankings. In addition, the software tool has the ability to handle

dynamic eects by considering a dierent array of weights corresponding to the considered timeperiod.

Various sets of criteria-weights can be determined according to dierent viewpoints expressed

by dierent groups (e.g., government, local authorities, interested groups). The dierent view-points can be examined as part of the sensitivity analysis of the MCA results, taking into con-sideration approaches to employ MCA in a fuzzy environment (Munda, 1995).



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The sensitivity analysis, which should be used for treatment of uncertainty in the MCA com-

ponent, should be complemented by risk analysis in the CBA. This might include setting the IRR(internal rate of return) or ROE (returns on equity) to reect levels of risk or changes to the

project design. The options related to the treatment of uncertainty with fuzzy sets and dierenttime horizons are explained in more detail in the following sections.

4. Treatment of uncertainty

4.1. Introduction

There are basically three ways for the treatment of uncertainty in evaluation:(a) probability-based methods (e.g., Bayes theorem),

(b) fuzzy sets,(c) informal methods (e.g., expert systems).

It is generally agreed that a fully rigorous treatment of uncertainty is impractical in cases of thesize and complexity tackled by the EFECT. On the other hand, the judgements on scores andweights for impacts are likely to be particularly `uncertain'. Also, the denition of index functions

is in most cases a rough approximation introducing additional `imprecision' to the end results,as shown in Fig. 3.

An initial uncertainty, in an observed or assigned (judgmental) value, results into an un-

certainty of the index value, which can be further magnied by an uncertainty in the indexfunction itself. The uncertainty in value and the resulting uncertainty in index are the mostcommon ones and can be dealt with in a variety of ways. In the EFECT, this type of un-

certainty can be described and incorporated into the assessment through the use of fuzzynumbers. Such treatment of uncertainty is considered as an add-on to the core model of

evaluation.

Fig. 3. Uncertainty in evaluating the value of a given criterion, using an index function.



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4.2. Uncertainty handled by EFECT

The method being used for fuzzy evaluation in the EFECT employs symmetric triangular fuzzy

numbers (STFNs). The basic equations (3)(5) of the core approach remain the same, but insteadof the crisp operators for addition, `+', and multiplication `', the fuzzy ones, `' and `', fromEqs. (6)(8) are employed.

L1YM1YU1 L2YM2YU2 L1 L2YM1 M2YU1 U2Y 6

L1YM1YU1L2YM2YU2L1 L2YM1 M2YU1 U2Y 7

kLYMYU k LY k MY k UX 8

They represent operations with TFN (triangular fuzzy number) and L is the lower bound, U theupper bound and M is the modal value, estimated by (9)

M L Ua2X 9

The rst three steps of the EFECT methodological framework essentially remain the same. Theonly change is in the comparison of alternatives needed for ranking. This needs to introduce an

additional operator `


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one-time permanent impacts (e.g., changes to the landscape) are multiplied by the respective

time, e.g., project life, short-term impacts (e.g., noise before construction of noise barriers) are multiplied by the re-

spective duration of impact,

long-term permanent impacts (e.g., impacts on houses that exist or will be built in the future,adjacent to a road) are multiplied by their estimate exposure times.

Furthermore, when both discrete and continuous criteria are used, a two-fold approach is em-

ployed: summations for discrete criteria and integration for criteria with continuous growthfunction over time. An example of the latter is `air pollution emissions' which is a function ba-

sically of trac volumes growing over time. Fig. 4 illustrates an example with four criteriaevolving during the time periods, where the following impacts are presented: (a) discrete transient

impacts (C1), one-time permanent impacts (C2), and (b) continuous short-term and long-term

impacts (C3, C4).Theoretically, in the time-frame evaluation, dierent sets of criteria-weights, in EFECT may

be used for dierent time horizons. For the sake of consistency and simplicity, only valuesshould change over time. Dierent weights could be used for construction and operation, in-dicating the dierent attitudes of the public, who are more willing to accept nuisance during the

construction of a project due to its `temporary' nature and the anticipation of benets, once it iscompleted.

6. Application of EFECT

The EFECT is used in a case study in Greece, for the appraisal of alternative road schemes in

Agios KonstantinosKamena Vourla area for the PATHE motorway project.The evaluation concerns the environmental impacts of four alignment options in the coastal

area of Agios KonstantinosAsproneriKamena Vourla. A team of experts selected the most

important environmental criteria. The impacts on the study area from the construction and op-eration of the motorway were examined both in the short-term and the long-term for each al-ternative option.

The application is done with the implementation of software developed for EFECT. It is aDecision Support System (DSS) comprising a MS Access Data Base application plus visual Basic

Fig. 4. Time-frame evaluation of impacts (example with 4 criteria).



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and MapObjects enhancements for additional presentation tools in the form of graphs and GIS

maps.

6.1. Step 1: structuring problem denition

Options: Four alternative options were examined: (I) maximum use of existing corridor; (II)bypass of Asproneri beach and Kamena Vourla; (3B) preliminary design option (with bridges andtunnels); and (III) inland scheme through LoggaAgnanti connection. Option III is a full devi-

ation of the coastal zone of Agios KonstantinosKamena Vourla, and consequently its con-struction has zero direct impacts on the natural and man-made environment of the coastal area.On the long-term, this option works together with options I and II, whereas for option 3B there is

no long term alternative other than directing trac through the existing coastal National Road(NR).

Objective: The general objective is the protection of the environment and minimization ofnegative impacts on the coastal area.

The degree of environmental protection for each option is expressed on an articial scale ofimpact scores, which corresponds to a verbal description as follows:

The scale is used for rating each criteria and the overall alternative options.Criteria: The criteria used are shown in Table 1.

The above denitions of options, criteria and objectives are dened using the EFECT frame-work as follows:

The user denes rst the project options (Table 2). The project options are further divided in

three geographical regions: Agios KonstantinosAsproneriKammena Vourla. The importance of

()4) strong negative impact()3) large negative impact()2) moderate negative impact

()1) small negative impact(0) no impact(+1) small positive impact(+2) moderate positive impact

(+3) large positive impact(+4) strong positive impact

Table 1

Criteria for evaluating the alternative solutions

Natural environment Operation nuisance Man-made environment

(1) Landscape (6) Air (10) Residential areas

(2) Soil (7) Noise (11) Land use

(3) Waters (8) Trac (12) City planning

(4) Ecosystems (9) Accidentshazards (13) Cultural heritage

(5) Natural resources (14) Public acceptance



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these regions can also be specied, e.g., as low-moderate-high (or any other value the user may

select).He also species the time frames for the evaluation, namely, short-term and long-term for this

example. The importance of these time frames can also be specied on the same user-dened scale.He may then dene (or select from an available list) criteria (Table 3) and sub-criteria (Table 4)

for the evaluation. Then, he may specify the importance of criteria on a scale of his own denition,for example, using gradations from 1 to 9 (Table 5).

These important values are the same ones applied throughout, namely, for geographical re-gions, time frames, and criteria or sub-criteria. They are used to generate the weights of the

evaluation, which, once computed can be further edited for ne-tuning by the user.

Table 3

Criteria for evaluation

ID Name

1 Natural environment

2 Operational nuisance

3 Man-made environment

Table 4

Sub-criteria for evaluation

ID Criterion ID to which sub-criterion refers Name

1 1 Landscape

2 1 Soil

3 1 Waters

4 1 Ecosystems5 1 Natural

6 2 Air

7 2 Noise

8 2 Trac

9 2 Hazards

10 3 Housing

11 3 Land use

12 3 Physical

13 3 Cultural

14 3 Public

Table 2

Project options

ID Name Description

1 Solution I Maximum use of existing corridor2 Solution II AsproneriKammena Vourla bypass

3 Solution 3B Approved solution (with bridges and tunnels)

4 Solution III Midland solution through LogoAgnanti link



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Also, a scale for rating the impacts can be specied (Table 6), using any range of numericalvalues.

6.2. Step 2: criteria weights

The relative importance of criteria is applied as a weight vector during the rating stage of the

method. The required weights of criteria are determined with Yagers method (Yager, 1977).According to this method, all criteria are compared to each other making a matrix of values foreach comparison pair. The value of a cell i, j (row i, column j) of the matrix is the ratio Wi/Wj,

namely the relative weight of criterion iover criterion j. The weight vector of all criteria results asthe main eigenvector of the comparison matrix. To apply the weights the vector is normalized in

the interval [0, 1].For the case study, the relative weights of criteria were determined with the application of the

Delphi method. Weights were supplied independently by three `experts': the designer of the roadproject, a geologisthydrogeologist, and a city plannerenvironmentalist. Thus, three dierent

Table 5

Importance of criteria

ID Verbal description Value

1 Least 12 Small 2

3 Weak 3

4 Less 4

5 Moderate 5

6 More 6

7 Strong 7

8 Great 8

9 Most 9

Table 6

Impacts rating

Verbal description Value

Strong negative impact )4

Large negative impact )3

Medium negative impact )2

Small negative impact )1

No impact 0

Small positive impact 1

Medium positive impact 2

Large positive impact 3

Strong positive impact 4



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`Viewpoints' were introduced. The results shown in the following are based on the `average' view

of the above three experts.

6.3. Step 3: rating and ranking the alternatives

The MCA tool of EFECT generates all possible combinations of project optionscriteriare-gionstimeframes. The user rates them accordingly. The criteria values are combined with a

summation function, which uses the score of each criterion multiplied by the respective weight ofthe weight vector.

To derive an overall score, which includes the three sections of the project ((S1) Agios Kon-

stantinos, (S2) Asproneri, (S3) Kamena Vourla), the relative weights for the three sections werecalculated with Yagers method, using the following assumptions: (i) the natural and man-made

environment of each area was considered, (ii) equal weight was given in comparing the two (ratio1), whilst, (iii) in comparing the man-made environment for each section weights were propor-

tional to the respective population of each area.The total score of each alternative option results on the same articial scale [)4, 4]. Negative

scores correspond to negative impacts on the environment, whereas positive scores correspond to

positive impacts.Hence, ranking of the alternative options is done considering as better solutions the ones with

higher scores. Fig. 5 presents in graphical form the results of the applications of the EFECT

software tool, for the long-term impacts of the alternative solutions.

6.4. Step 4: Exploring the results

For the purposes of the case studies, step 4 considered only the time dimension. The applicationof EFECT has provided the following results: The best solution for the overall project of Agios KonstantinosKamena Vourla Bypass is op-

tion II, namely the midland solution behind Knimida Mountain. This solution exceeds all oth-er, both in the mid-term and long-term. It is the only solution with positive impacts in the mid-term and even greater benets in the long-term.

As regards the remaining solutions, options I and II are better than option 3B, as they have

smaller negative impacts to the environment. Between options I and II, option II is preferable,due to less impacts to the anthropogenic environment. In the long-term, both solutions haveimportant positive impacts to the area.

Fig. 5. Long-term results for the study.



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Solution 3B, in the mid-term, has the largest negative impacts to the environment, which in thelong-term become even larger, as this option leaves no space for growth when trac volumes

approach the capacity of the road section. This results in reloading the existing NR with the

associated problems to the communities of the area.Therefore it is concluded that option 3B, which was the preferred solution at the time, in reality is

a choice inferior to options I, II and III, considering spatial impacts and long-term eects from theenvironmental point of view. This is due to the fact that these solutions have smaller environ-mental impacts, and in the long-term resolve the trac and urban problems of the coastal zone.

The application of EFECT suggested the adoption of one of the options I, II, or II, and preferablyof option III, as being the most appropriate from the environmental point of view, especially in

the long-run.

7. Conclusions

The paper presented EFECT, a comprehensive, generalized methodological framework forenvironmental assessment of transport initiatives, with the following features, some of whichexhibit unique aspects:

the combined use of MCA and CBA methods, the simplicity in the use and understanding, based on an additive function, and a core ap-

proach, the use of established techniques for determination of weights, index functions and ranking, the use of a hierarchy of criteria, which can be expanded or collapsed accordingly, based on the

needs of the evaluation,

the explicit incorporation of the spatial distribution of impacts through the use of regionalweights,

the incorporation of the time dimension in the analysis allowing to consider dynamic eects, the handling of uncertainty either through sensitivity analysis or with the use of fuzzy numbers.

Based on the EFECT methodological framework, software for the implementation of EFECTwas developed combining the above-presented tools with a GIS tool. The presented application ina case study in Greece has demonstrated its advantages over other conventional approaches,

especially in the comparison of spatial impacts and in the assessment of impact evolution overtime.

It is an easy to use framework, friendly to the user and very exible. It allows to include any

number and type of criteria, and to compare any number of options over space and time. Thesoftware tool presented covers the core approach of the EFECT, plus the sensitivity testing and

time assessment capabilities. It can be easily extended to include fuzzy set evaluation and otherforms of scoring functions. However, the summation function used in the core approach provides

better intuitive understanding and it is easier to explain to DMs.The capability of EFECT to look into dierent geographical areas with a dierent perspective

and examine dierent time-horizons has been proven an additional advantage in the evaluation oftransport projects, and especially from the environmental point of view.

Last, but not least, EFECT is a modular system that can be used both for strategic and detailedevaluation of transport initiatives for all modes and for all kinds of transportation networks. It



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can provide an individual or the public authorities (national, European Commission) with the

appropriate methodological framework and tools regarding the Environmental Assessment. It isnoted that due to its exibility and open structure, the framework can be expanded to include

other aspects of the evaluation of transport projects or initiatives.

Acknowledgements

The present paper is based on research carried out partly with European Commission fundingunder the IV Framework Programme for Research and Development, and in particular regarding

the EUNET and BRIDGES research projects.

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