The Analytical Hierarchy Process (AHP) is a widely used decision-making tool, particularly in complex decision-making scenarios involving multiple criteria and alternatives. In the context of highway alignment planning in Nepal, AHP can be particularly beneficial due to the country's varied topography, limited resources, and the need for an integrated approach to infrastructure planning. Here's how AHP can be applied to highway alignment planning in Nepal:

1. Objective of the Study

The primary aim of using AHP in highway alignment planning is to identify the most suitable alignment for a proposed highway route that takes into account various competing criteria like cost, environmental impact, safety, land acquisition, and social benefits. The study would involve the use of an expert questionnaire survey to collect opinions from engineers, planners, and other stakeholders who are knowledgeable about Nepal's geographical and infrastructural realities.

2. Key Components of the AHP Approach

AHP works by breaking down a complex decision problem into a multi-level structure:

• Goal: The ultimate goal is to select the best highway alignment from several alternatives.
• Criteria: Different criteria (e.g., cost, environmental concerns, ease of construction, safety, etc.) are identified, which impact the final decision.
• Sub-criteria: These are more detailed factors within each criterion. For example, under "cost," you might include land acquisition cost, construction cost, and maintenance cost.
• Alternatives: Different possible highway alignments (routes) are proposed.

3. Steps Involved in AHP for Highway Alignment Planning in Nepal

a) Identification of Criteria and Sub-Criteria

• Cost: Construction and maintenance costs, land acquisition, etc.
• Environmental Impact: Ecological damage, air and noise pollution, biodiversity concerns.
• Safety: Traffic safety, accident rates, risk of landslides or floods.
• Social Impact: Displacement of communities, access to social services, local employment opportunities.
• Geotechnical Considerations: Terrain, soil stability, geological hazards.
• Political or Legal Issues: Land ownership, local politics, permits, and regulations.

b) Survey Design

• An expert questionnaire is designed to collect subjective judgments from stakeholders (experts, engineers, planners, environmentalists) about the relative importance of each criterion and the relative performance of different alignments with respect to these criteria.
• The questionnaire would use pairwise comparisons (e.g., "Which criterion is more important, cost or environmental impact?") to rate the relative importance of each factor.

c) Pairwise Comparisons

• Using a scale of 1 to 9, experts compare the relative importance of each pair of criteria and sub-criteria. A rating of "1" means that both criteria are equally important, while a rating of "9" means one criterion is extremely more important than the other.

d) Consistency Check

• AHP also includes a consistency check to ensure that the pairwise comparisons made by experts are consistent. This is done using a consistency ratio (CR), where values less than 0.1 typically indicate consistency in judgments.

e) Weight Calculation

• Once pairwise comparisons are made, AHP uses a mathematical procedure (typically an eigenvector method) to calculate the weight or relative importance of each criterion. This weight reflects how much each criterion should influence the final decision.

f) Scoring of Alternatives

• Each highway alignment is evaluated with respect to the identified criteria and sub-criteria. Experts score each alignment, and the scores are normalized for comparison.

g) Final Decision

• AHP aggregates the weighted scores for each alignment option to produce an overall score. The alignment with the highest score is considered the most optimal based on the criteria and expert opinions.

4. Potential Benefits of Using AHP in Highway Alignment Planning in Nepal

• Holistic Decision-Making: AHP considers both tangible and intangible factors, making it a comprehensive tool for highway planning in a developing country like Nepal, where the decision involves environmental, social, and technical considerations.
• Expert Input: The involvement of experts ensures that the decision-making process reflects practical experience and local knowledge.
• Transparency: The structured approach of AHP provides transparency and justifies decisions, making it easier to explain the rationale behind selecting a specific alignment.
• Conflict Resolution: AHP helps address potential conflicts among stakeholders by clearly outlining the importance of various criteria and how they influence the final choice.

5. Challenges in Nepal

• Complex Terrain: Nepal's mountainous and difficult terrain can make some criteria, like construction cost and environmental impact, harder to assess.
• Limited Data: Accurate data may be scarce, especially for factors like long-term environmental effects or social impacts.
• Stakeholder Disagreement: There may be disagreements among local stakeholders, which could affect the reliability of the expert judgments.
• Resource Constraints: Implementing the AHP method requires resources, both in terms of time and funding, which might not always be readily available in the context of Nepal's infrastructure planning.

Use of Analytical Hierarchy Process (AHP) in Highway Alignment Planning in Nepal: An Expert Questionnaire Survey

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• Started 3 days ago

# 204

Dear Milan Shrestha, Shuva Raj Neupane and Binaya Kumar Mishra

I have read your paper:

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Farid Leguebedj added a reply

8 hours ago

Dear Farid

Thank you for your detailed observation. My response to them is in lines initialized as NM

The Analytical Hierarchy Process (AHP) is a widely used decision-making tool, particularly in complex decision-making scenarios involving multiple criteria and alternatives. In the context of highway alignment planning in Nepal, AHP can be particularly beneficial due to the country's varied topography, limited resources, and the need for an integrated approach to infrastructure planning. Here's how AHP can be applied to highway alignment planning in Nepal

NM - I agree that AHP is heavily used in decision making, but not in complex scenarios. Its heavy use does not necessarily mean that a scenario is complex. Complexity is seen in many other issues like alternatives precedence, inclusion and exclusion, targets for criteria, problems involving changes along time, multiples relationships among criteria, etc. None of them can be not even modelled in AHP, let alone solve the problem. Of course, that you need to consult road experts, but most probably they are not aware of the AHP mathematical principles, let alone its structure. You request their opinions and suggestions on fields that they dominate, but probably are not proficient in MCDM, which is the do main of academics and researchers.

1. Objective of the Study

The primary aim of using AHP in highway alignment planning is to identify the most suitable alignment for a proposed highway route that takes into account various competing criteria like cost, environmental impact, safety, land acquisition, and social benefits. The study would involve the use of an expert questionnaire survey to collect opinions from engineers, planners, and other stakeholders who are knowledgeable about Nepal's geographical and infrastructural realities.

NM – Agreed

2. Key Components of the AHP Approach

AHP works by breaking down a complex decision problem into a multi-level structure:

NM- Breaking down is very useful for analyzing a MCDM problem but not for solving it. AHP constitutes a system, and as that, you cannot break it down. Evern Saaty said that it is a system. It is like in a car optimizing the engine, the body, the transmission, the aerodynamicsr and then adding them up. You can’t, because the engine, for instance, is tightly related to the other subsystems. For example, a criterion can state that the speed must be 120 km/hr, and this, of course depends of the engine, the aerodynamics, the air conditioning subsystem consumption, the transmission, the tires, etc.

• Goal: The ultimate goal is to select the best highway alignment from several alternatives.

NM – You forgot to put “ Subject to a set of criteria”

• Criteria: Different criteria (e.g., cost, environmental concerns, ease of construction, safety, etc.) are identified, which impact the final decision.

• Sub-criteria: These are more detailed factors within each criterion. For example, under "cost," you might include land acquisition cost, construction cost, and maintenance cost.

• Alternatives: Different possible highway alignments (routes) are proposed.

NM- Agreed

3. Steps Involved in AHP for Highway Alignment Planning in Nepal

a) Identification of Criteria and Sub-Criteria

• Cost: Construction and maintenance costs, land acquisition, etc.

• Environmental Impact: Ecological damage, air and noise pollution, biodiversity concerns.

• Safety: Traffic safety, accident rates, risk of landslides or floods.

• Social Impact: Displacement of communities, access to social services, local employment opportunities.

• Geotechnical Considerations: Terrain, soil stability, geological hazards.

• Political or Legal Issues: Land ownership, local politics, permits, and regulations.

b) Survey Design

• An expert questionnaire is designed to collect subjective judgments from stakeholders (experts, engineers, planners, environmentalists) about the relative importance of each criterion and the relative performance of different alignments with respect to these criteria.

NM – It is absolutely correct to ask the opinion and advice of experts, no doubt about it, but in general they do not select the best route, since that is the job of the DM and the MCDM method he uses. The road experts are off of this.

• The questionnaire would use pairwise comparisons (e.g., "Which criterion is more important, cost or environmental impact?") to rate the relative importance of each factor.

NM- In my opinion using pair-wise comparisons is valid, but it is not valid and without mathematical or rational point of view, that the expert or the DM can establish a preference. In the example you put there is a financial guy, and the environmentalist. Therefore, how can they agree on a preference, if none of them is expert in the other guy field?

c) Pairwise Comparisons

• Using a scale of 1 to 9, experts compare the relative importance of each pair of criteria and sub-criteria. A rating of "1" means that both criteria are equally important, while a rating of "9" means one criterion is extremely more important than the other.

NM-The Fundamental Scale is a fabricated assumption, since it pretends to replicate the Weber-Fechner Law in psychology when establishing the relationship between stimuli and responses, a log. On

In AHP you do not have incentives or stimuli but simply a numerical preference. Extract your own occlusions

d) Consistency Check

• AHP also includes a consistency check to ensure that the pairwise comparisons made by experts are consistent. This is done using a consistency ratio (CR), where values less than 0.1 typically indicate consistency in judgments.

NM – Correct, and it is based on a simulation exercise, nothing wrong about it. What is very wrong is to decree that the whole estimates matrix MUST be transitivity, and if it not, forcing the DM to correct his estimates. What do you think about this? Where is mathematics or common sense here?

e) Weight Calculation

• Once pairwise comparisons are made, AHP uses a mathematical procedure (typically an eigenvector method) to calculate the weight or relative importance of each criterion. This weight reflects how much each criterion should influence the final decision.

NM- Sorry. this is not exact. The weights are only a measure of criteria relative importance, and even when intuitively it is believed that they can evaluate alternatives, it is not so. What may evaluate the alternatives are the dispersion of values within each criterion, not the criterion as a whole. Please, look at Shannon’s Theorem

f) Scoring of Alternatives

• Each highway alignment is evaluated with respect to the identified criteria and sub-criteria. Experts score each alignment, and the scores are normalized for comparison.

NM- Agreed although the DM determines using a MCDM method the scores, not the experts

g) Final Decision

• AHP aggregates the weighted scores for each alignment option to produce an overall score. The alignment with the highest score is considered the most optimal based on the criteria and expert opinions

NM- This is possible one of the many AHP drawbacks. Because, as said, the matrix is a system you cannot simply add, you must work with intersections. Remember that not always a result is equal to the sum of the parts, remember the car example, and this is real, not an assumption. See System Theory, and the car example.

4. Potential Benefits of Using AHP in Highway Alignment Planning in Nepal

• Holistic Decision-Making: AHP considers both tangible and intangible factors, making it a comprehensive tool for highway planning in a developing country like Nepal, where the decision involves environmental, social, and technical considerations.

NM- Like any other method, what is new?

• Expert Input: The involvement of experts ensures that the decision-making process reflects practical experience and local knowledge.

NM- Yes, independently, and that is not very useful, since it is very human to support what one believes. Explain it is another issue, something that AHP is consisting in not justifying, and is not surprising that nobody cares or respond. The reason, always in my opinion and those from others along 10 years in RG, is that there are no answers because, nobody, in this area at least, can explain something that is unexplainable. For instance, AHP asserting that the transitive matrix, reflecting the moods and intention of a person, or even a group of persons, is applicable to the real-world. Nice assumption, but irreal and that goes again common sense. It comes out of the dark without explanation. It is inevitable not to get suspicious.

• Transparency: The structured approach of AHP provides transparency and justifies decisions, making it easier to explain the rationale behind selecting a specific alignment.

NM- Could you mention at least one or the user has to believe it by decree? The rational is to use a MCDM method, since there is no rationality in AHP.

• Conflict Resolution: AHP helps address potential conflicts among stakeholders by clearly outlining the importance of various criteria and how they influence the final choice.

NM- Have you ever been a in meeting with stakeholders trying to demonstrate them ou put their money based on your intuition? I wouldn’t recommend it

5. Challenges in Nepal

• Complex Terrain: Nepal's mountainous and difficult terrain can make some criteria, like construction cost and environmental impact, harder to assess.

NM-I agree with you. I have been in Nepal andtravelled some of its routes like Kathmandu / Pokhara (beautiful place by the way)

• Limited Data: Accurate data may be scarce, especially for factors like long-term environmental effects or social impacts.

NM- Well, you can use extreme values and work in an interval, but you cannot do that in AHP, even using fuzzy

• Stakeholder Disagreement: There may be disagreements among local stakeholders, which could affect the reliability of the expert judgments.

NM- Of course there are often disagreements among stakeholders and also experts, specially related to funds and personnel. But each stakeholder tries to support his own activity and this must be respected without discussions because they know what is needed in his area. This is not in AHP procedure which allows a DM taking decisions on aspects that may affect thousands of people. This has a name, and it is ‘dictatorship’ as defined by Arrow’s Incompatibility theorem. You cannot vote for others, and years ago I had the privilege to discuss this issue with Dr. Saaty. As a bottom line, it is desirable that each stakeholder expresses as wished, and it is the MCDM method to find a compromise solution or balance between them, something that AHP is not designed for.

• Resource Constraints: Implementing the AHP method requires resources, both in terms of time and funding, which might not always be readily available in the context of Nepal's infrastructure planning.

NM- I never have seen that AHP uses resources, because for that it should be using limits to their availability. Resources are normally existent in any project; what does not mean that they can be used in the amount required by each project. In that case, it could be useful to shorten expectations.