Multiactor Participatory Decision Making in Urban Construction Logistics

Construction is required to create more attractive, sustainable, and economically viable urban areas. However, transportation of construction-related goods and personnel potentially causes negative impacts. A lack of early and accurate information on how the construction site and goods will be organized can lead to disputes and disruptions that harm the construction work and the surrounding community. A method is presented for evaluation of alternative construction logistics measures in a multiactor participatory setting. The method, MAMCA software, has been demonstrated in a role-playing setting with 20 students at the Amsterdam University of Applied Sciences in the Netherlands.

torical city centers. Because it also concerns heavy goods vehicles, additional nuisance is caused. Construction material is often heavy, necessitating large vehicles. Due to the size of those vehicles, even more so when they are loaded, damage to infrastructure can be considerable compared with other-lighter weight-freight vehicles (4,9). Research by students in Amsterdam in 2011 shows that 18% of heavy goods vehicles are related to construction, as are 43% of cargo vans (excluding construction waste). Another distinctive character is the fragmented nature of the construction industry. Consequently, this leads to the movement of a relatively high number of nonoptimized freight vehicles to and from these sites. Additionally, congestion around construction sites can increase substantially because of waiting times for vehicles to be loaded and unloaded (4). Personnel are also moving toward the construction sites every day, causing additional flows. At the same time, these sites produce a lot of waste, and outgoing flows should therefore not be neglected (10,11). Although in this way transportation related to construction sites causes negative effects for society and the environment, there is principally a large potential gain for the stakeholders directly involved in a construction project (e.g., logistics service provider, building contractor). Because there are congestion and nonoptimized flows, improved construction logistics could save from 10% to 30% of project costs (4). Altogether, the transportation of goods and personnel to, from, and around urban construction sites causes social, economic, and environmental problems, as follows: • Social. Construction-related transport leads to nuisance in regard to noise, physical hindrance, and safety issues, and annoyances from the occupation of parking space.
• Economic. Inefficient planning of resources, material, and personnel, leads to unnecessary costs and construction delays. Construction materials have a low value density. Therefore, transportation costs are an important part of total construction costs. Road closures during construction works often lead to reduced income for surrounding businesses (e.g., shops and restaurants) and traffic delays.
• Environmental. Construction-related transport is carried out with heavy or old polluting vehicles that emit harmful emissions and, owing to inefficient planning, often spend a long time idling.
All the aforementioned problems result in a societal challenge: How to keep the construction site surrounding community a livable and acceptable place to work, life, and visit while improving energy efficiency and productivity of construction projects at the same time?
The solution needs to be found both in the construction and logistics processes themselves, as well as in the management of people and the expectations and criteria of the various stakeholders. The construction and logistics processes concern challenges in regard to the optimization of resource planning in a dynamic setting, while As elaborated earlier, there is an enormous potential to make construction logistics more sustainable by paying attention to the three aspects of sustainability (i.e., economic, environmental, and social) (5). In this light, different measures have been implemented with the aim of making urban freight transport more sustainable. Measures include, among others, time windows, weight and size restrictions, low emission zones, congestion charging schemes, urban consolidation centers, night deliveries, and the deployment of cargo bikes (5,19). However, owing to its nature, construction logistics demands tailored solutions. For instance, a solution with clean vehicles such as cargo bikes or small electric vehicles (EVs) is limited because of the low payload. At the same time, construction sites only cause intensive transport flows temporarily. There are nevertheless some measures specifically targeting more efficient and sustainable construction logistics. The potential of transport of construction materials toward urban areas by using waterways and railways has been studied in France, Belgium, and Japan (20,21). In this way, congestion can (partly) be avoided, while the use of barge or train leads to fewer emitted pollutants. A construction logistics plan (CLP) has been implemented by Transport for London (22) and in Utrecht (7). CLPs provide a framework to manage different types of freight vehicle movements to and from construction sites better (23). The most broadly trialed measure with regard to construction sites is consolidation centers (24). In line with a regular urban consolidation center (UCC), the purpose is to bundle goods from outside the city by cross-docking them for subsequent deliveries. That way, efficiency of deliveries can be increased, leading to a higher load factor, fewer vehicles, and fewer vehicle kilometers (24,25). Consolidation centers either serve a certain area such as a city center or are site specific. With regard to the latter, several construction consolidation centers have been used to serve specific sites, in which the use of the consolidation center was made compulsory by the manager of the construction site, to better control the movement of vehicles (26). Projects that included the temporary use of consolidating construction deliveries are Terminal 5 at Heathrow Airport, the rebuilding of the Potsdamer Platz in Berlin, and Hammarby in Stockholm (24,25). The London Construction Consolidation Centre (LCCC) served four major construction sites and eliminated the use of articulated vehicles, while simultaneously the use of vans was significantly reduced because of increased efficiency. In total, it was estimated that the LCCC contributed to a reduction in vehicles to the four sites of 60% to 70%, resulting in a reduction of 70% to 80% of CO 2 emissions (22).
However, while implementing different measures, authorities often do not pay enough attention to the transport sector itself. Depending on the measure, this can lead to even more complicated deliveries. As a result, there is insufficient attention to economic sustainability (27). Altogether, this demands a more comprehensive stakeholder involvement when it comes to making construction logistics more sustainable. The simultaneous importance and difficulty of including different stakeholders in the decision-making process have been raised by several authors [e.g., Lindholm (2), Reed (28), and Macharis (29)]. The MAMCA developed by Macharis provides a structured approach to include different stakeholders early in the decision-making process with regard to the simultaneous evaluation of alternative policy measures, scenarios, or technologies (29,30). The MAMCA allows evaluating the impact of different measures with regard to the criteria of different stakeholders. It is therefore very well suited to complex decision-making processes where many management concerns challenges of transparency, communication, and engagement. Both are complicated considering the high density and sensitive environment of urban construction sites and the number of stakeholders involved, with often contradictory criteria, as shown in the following examples: • Public authority: "No heavy vehicles allowed in the city after 11 a.m." • Client: "There is no space available for inventory on site." • Contractor: "I need to start at 7 a.m. to manage all the transport within the time window." • Employees: "I want to travel to work before traffic gets congested." • Logistics service provider: "I want to optimize my trip to multiple destinations." • School: "Our kids need to travel to school safely, and it has to be quiet after 8.30 a.m." • Resident: "I do not want to wake up by traffic noise." This paper presents a method for evaluation of alternative construction logistics measures in a multiactor participatory setting. The method has been demonstrated in a role-playing setting with 20 students at the Amsterdam University of Applied Sciences in the Netherlands. The next section first elaborates on the literature study with regard to making construction logistics more sustainable. Then the third section elaborates on the methodology-multiactor multicriteria analysis (MAMCA)-that allows taking different stakeholders and their respective objectives into account with regard to different alternatives that possibly mitigate the negative effects of construction logistics. This is followed by the case study concerning planned construction works in the city of Amsterdam. The results are presented and discussed, followed by the conclusions.

State of the art
In past years, strategic research has led to increased understanding of construction logistics processes. For example, Gilchrist and Allouche have clearly described the issues that are often encountered around urban construction (12). Stakeholder specific requirements have been identified by, among others, Landqvist and Rowland (13). Also, possible measures and strategies to optimize constructionrelated transport have been proposed by Quak et al. (14) and van Merrienboer (15).
However, the process used for determining the effectiveness of measures from a multiactor perspective has not been the subject of research before. This process is of relevance, since measures may have positive effects for one stakeholder while having negative, unexpected effects for another. Early accurate insight into the consequences for and from construction-related transport needs to be obtained and discussed, to avoid disputes and disruptions harming the construction work and the surrounding community. In the past, urban freight transport in general has been neglected by city planners (16). Only recently has more attention been given to it because of the effects on mobility and quality of life (17). Despite the increasing attention to urban freight transport, certain movements of goods including construction mostly remain neglected (2). Although stakeholders are increasingly involved in construction projects, it merely applies to the project itself, and transport receives little or no attention (18). stakeholders from several areas and backgrounds with different interests are involved. It can be used for many applications and has principally been used for transport-related decision-making problems [for an overview, see Macharis et al. (31)]. It has been used for several real decision-making problems (32,33). The next section elaborates on the methodology.

Methodology
The MAMCA is an extension of existing multicriteria decision analysis methods, which allows taking quantitative as well as qualitative information into account. While traditional multi-criteria decision analysis methods have a common value tree for all stakeholders, the MAMCA allows the evaluation based on a separate value tree for each stakeholder. In this way, decision makers and experts can evaluate policy measures with regard to the criteria of different stakeholders. Stakeholders are explicitly included in the analysis and the decision-making process. They get an insight into the impact of measures on their own criteria as well as on those of others (31). The MAMCA consists of seven steps and is illustrated in Figure 1. In this section, each step is briefly elaborated.
During the first step of the MAMCA, the problem as well as some alternatives are identified. The alternatives can be policy measures as mentioned in the previous section (e.g., LCCC). Next to the different alternatives, there is a business as usual (BAU) alternative representing the current situation. Subsequently, there is a stakeholder analysis. Stakeholders are those actors who affect a problem as well as those who are being affected by it (29). Within the city context, the most commonly identified stakeholders are the receivers, shippers, logistics service providers (LSPs), local authorities, and citizens (5,34,35). The list is, however, not predetermined, and it depends on the decision-making problem. In the same step, the objectives of the stakeholders are identified. This is done based on the literature and consultation with the involved stakeholders. Afterward, the objectives are translated into criteria, and the stakeholders themselves attach weights to them by using the analytical hierarchy process (AHP) pairwise comparison. The fourth step couples one or more measurable indicators to each criterion, which allows evaluating each criterion with regard to the different alternatives. This is done in the fifth step by aggregation in an evaluation matrix and can be done by the stakeholders or by experts. Different group decision support systems are available [e.g., PROMETHEE, AHP, ELECTRE; see Macharis et al. (31)]. The sixth step involves visualization of the results in a uniactor and multiactor view by which different visualizations are possible, for example, criteria contribution chart and geometrical analysis for interactive aid plane view. A sensitivity analysis can be conducted to examine the robustness of the results. Finally, the results provide input for a structured discussion as it becomes clear to what extent each alternative contributes to the criteria of the different stakeholders (31). Recently, software has been developed to allow the simultaneous evaluation of different policy measures in a multiactor setting (36). The software allows one to set up a project including alternatives, to create relevant stakeholders for the project, and to attach criteria to these groups. This has been applied to a real case concerning construction logistics in Amsterdam, where students are actively involved in the role of the different stakeholders.

CaSe and Software deMonStration
The MAMCA software has been demonstrated for construction logistics with 20 students at the Amsterdam University of Applied Sciences (AUAS). The case is an actual construction project of the university campus, planned for 2015 to 2018. During the software demonstration in May 2015, the construction project was still in the tender phase, in which the logistics would be used as part of the most economically advantageous tender approach. In the following paragraphs is a discussion of the construction project in more detail, alternative solutions to make the transport to the building site more efficient and sustainable, and stakeholder groups to which the students were assigned.

Case
AUAS is building a new campus building for 28,000 students in the inner city of Amsterdam, called the Conradhuis. Sustainability is important for AUAS and, in line with that, the organization aims to build the most sustainable campus of the Netherlands. However, the construction project is complex for several reasons. First, the location of the construction site, which is near the Amstel River, is next to a very busy intersection (Marnixstraat-Wibautstraat). During construction works, part of the campus is already operational with many students and employees coming and going. There is barely any space for holding the stock of construction materials on site. Moreover, the construction site is within the environmental zone of Amsterdam. Next, the construction site is surrounded by campus buildings and student apartments that are already in use. This means that there are many citizens, cyclists, and pedestrians around the site. Recently, the University of Amsterdam, a close partner of AUAS, has experienced several disputes with local residents during construction works, which led to delays and negative public relations. AUAS recognizes the importance of a multiactor-multicriteria approach.
alternatives On the basis of analysis of the local situation, stakeholder consultation, and the literature, three possible alternatives were identified in close collaboration with experts involved in the project and presented to the students. First, BAU represents the situation in which no action is taken, meaning that freight vehicles arrive and depart irregularly during the day, leading to fragmented deliveries. The three potential logistics solutions are • Night deliveries. Goods are delivered with trucks at night (before morning peak hours); • Bundling hub + EVs. Imposing a central delivery address at the city border, after which goods are consolidated and delivered with electric freight vehicles to the construction site; and • Bundling hub + waterway. Imposing a central delivery address at the city border, after which goods are consolidated and delivered by waterway transport near the construction site.

Stakeholder groups
Five stakeholder groups as well as their objectives are identified as being involved in the project. The objectives are based on the local situation as well as a literature review focusing on city (construction) logistics (32). The five stakeholder groups are LSP, supplier (construction wholesale), building contractor (receiver), citizens, and municipality. The students were assigned to these groups and asked to project themselves into the stakeholder's position and objectives. To help them, they were informed about the various possible criteria of each stakeholder group. For example, citizens desire a certain maximum noise level; public space (e.g., to park the car, or for children to play); and traffic safety. Suppliers and builders want to deliver and receive a high level of service with low transport costs. LSPs aim for profitable operations and satisfied employees. The municipality wants to have an attractive environment for citizens and companies, with little enforcement. An overview of all the criteria per stakeholder group is presented in Table 1.

Criteria weights
The students, alias specific stakeholders, were first asked to give weights to their criteria by using the pairwise comparison method (scale of 1 to 9, AHP). Each group was composed of four students who discussed the attribution of the weights to the criteria. Table 1 shows the weights of the respective criteria. Per stakeholder group, the sum of the weights is 1. The weights already give a first insight into where the preferences of the different stakeholders are with regard to their criteria.
The LSP attributes an almost equal importance to four of its criteria except employee satisfaction. For the supplier, the quality of the service and the quality of the pickups are by far more important than its other two criteria, green concerns and transportation costs. Especially with regard to the latter, this is remarkable. In line with this, the building contractor attaches more importance to convenient deliveries and security than to the costs of transportation and green concerns. Next, the municipality values the quality of life of its citizens and an attractive business climate as most important, while the weights attached to the other three criteria are relatively low. Finally, the citizens find traffic safety the most important, followed by public space ( Table 1).

evaluation of alternatives
Evaluation of the alternatives was executed by the students, still in their stakeholder group. Within such a workshop setting, this is a good way to come directly to results, but keeping in mind that this impact analysis of the alternatives on the criteria is based on their perception of the situation and not based on objective research. For the evaluation, the PROMETHEE method is used. For each alternative, every stakeholder group evaluated to what extent BAU and the three alternatives contributed to each criterion. The evaluation scale used is qualitative (very negative, negative, neutral, positive, very positive). In the results, this is visualized in the figures in a quantitative way: −2 is very negative, −1 is negative, 0 is neutral, +1 is positive, and +2 is very positive. During the final discussion, each stakeholder group explained the reason they attributed the weights in the way they did. Additionally, they clarified their evaluations of the alternatives.

Multiactor Perspective
The MAMCA analysis leads to a multiactor view on the three alternatives and BAU. The results are shown in Figure 2. On the x-axis, the different stakeholder groups are displayed. The y-axis, ranging from −1.8 to 1.8, shows the evaluation scale. This represents the (qualitative) evaluation scale as used for the evaluation of the different alternatives with regard to the criteria (fifth step; see previous section). The colored lines in the figure represent the alternatives in which the location on the vertical dotted line corresponds to the evaluation score for the respective stakeholder group. The first observation that can be made from this figure is that the current situation (BAU) contributes the least to criteria for almost all stakeholders. It is only for the supplier that the alternative with the bundling hub and waterway contributes slightly less to that stakeholder's criteria. From this first observation, a tentative conclusion can be drawn that every way of delivering to the construction site is an improvement vis-à-vis BAU. By looking at the different uniactor perspectives, the contribution of BAU with regard to each criterion can be explained in more detail (see next section). However, apart from this, there are differences among contributions of the alternatives to the criteria of stakeholders. For none of the stakeholders is the alternative of deliveries during the night the one that contributes most to their criteria. With regard to the other two alternatives, bundling with EVs contributes by far the most to the criteria of both the LSP and the supplier. Similarly, bundling but by making use of the available waterways contributes most to the criteria of the building contractor, citizens, and municipality. Especially for the latter, both bundling alternatives contribute relatively well to its criteria. From this first analysis, it becomes clear that bundling deliveries provides a good alternative to regular deliveries since it contributes well to the criteria of all stakeholders. There is, however, a difference when it comes to the transport mode for carrying out the subsequent consolidated deliveries. A closer look at the different uniactor views shows in more detail how each alternative contributes to the criteria of each stakeholder.

uniactor Perspectives
Here the uniactor perspectives of the LSP and the municipality are elaborated in more detail. As shown in Figure 2, only the bundling with EVs contributes relatively well to the criteria of the LSP. A more detailed view of the criteria is shown in Figure 3. The x-axis represents the different criteria. The colored lines in the figure show the alternatives, while the bars indicate the weights that were given to the respective criteria by this stakeholder group. The criteria weight (−1 to 1) is shown on the left side of the y-axis and the evaluation score (−3 to 3) on the right side. The score of each alternative is a calculation of the separate scores of each alternative to the criterion, based on the defined PROMETHEE parameters.
The bundling hub with EVs contributes the most to all criteria except for the criterion on the viability of investment. The reason for this-as explained by the students-is that an LSP has to invest in EVs for delivering to the construction site, while it is difficult to recoup this investment. In addition, the LSP expects additional costs for the consolidation center. The same reasoning applies to the bundling with last-mile deliveries by water in which the LSP also considers the extra costs of deliveries by barge. At the same time, both alternatives contribute the most to green concerns because it is expected that more efficient deliveries resulting from bundling and subsequently using cleaner transport have a positive impact on the environment. BAU contributes the least to this criterion. When it comes to the profitability of operations, the three alternatives score equally higher than BAU. The reason is that the LSP assumes that the tender is won when a cleaner alternative is provided to regular inefficient deliveries by trucks. The current situation and the bundling with EVs both contribute relatively well to the high service level and to employee satisfaction. For the latter, the explanation is that the employees are truck drivers, and in those two alternatives, they can execute their job. This partly ceases with deliveries via the waterway, while deliveries during the night are not preferred. The high service level is attributed to BAU and the EVs because the LSP expects that it is able to maintain its service level with regular last-mile deliveries by trucks during working hours. Night deliveries contribute the most only to the viability of investment because, together with BAU, the current fleet can be used.
The LSP is only one of the three so-called economic stakeholders directly involved in the project. The two other stakeholder groups, citizens and municipality, are more indirectly involved. With regard to the latter, an active role can be played in different ways. For instance, the municipality can introduce restrictions and leave it to the other stakeholders as to how to supply the construction site. It can also support more optimal deliveries by, for instance, providing subsidies or a consolidation hub (26). However, in this workshop, the alternatives and the position of each stakeholder group were not specified to such a detailed extent, and it was left to students to fill in the details. During the final discussion, they had the opportunity to clarify this situation. The uniactor view of the municipality is shown in Figure 4.
Both bundling alternatives contribute the most to the criteria of the municipality. The use of waterways especially contributes to each separate criterion. With use of the waterway for last-mile deliveries, no construction materials are transported at all via urban roads. As a result, this has a positive impact on the criterion on infrastructure (accessibility). With regard to the quality of life and the business climate, there is limited air pollution, no impact on road safety, and no noise nuisance because of the deliveries to and from the construction site. That makes the city more attractive for both citizens and companies. Finally, because roads are avoided, no measures have to be implemented to make city distribution more sustainable; consequently, there are no costs. The other bundling alternative with consolidated deliveries by EVs contributes equally to the criteria on the business climate and the quality of life. In regard to the infrastructure, however, EVs-although efficiently loaded-still compose a part of road traffic. This alternative contributes the least to the cost of measures since the municipality assumes that subsidies have to be provided for the EVs, and that makes it relatively expensive. Night deliveries contribute less to the criteria; that is mainly because it contributes the least to the criterion with the highest weight, quality of life. The reason for this low score is the expected noise nuisance during the night, which negatively affects citizens' night rest. The low contribution to the criterion on enforcement is because special permits to allow deliveries during the night have to be issued.
For infrastructure, it is expected that avoidance of deliveries during the day alleviates congestion. Therefore, this alternative scores relatively well here. Overall, BAU contributes the least to the criteria since inefficient deliveries with (heavy) vehicles negatively affect the accessibility, quality of life, and business climate. At the same time, no specific measures are implemented for these deliveries. As a consequence, BAU contributes in a positive way to the criteria of enforcement and costs of measures.
The more detailed descriptions of two stakeholders show how the uniactor view explains the results behind the overall multi actor perspective. This provides more insight into the reasoning of the stakeholders. As elaborated earlier, it depends largely on how much detail the alternatives have. In this workshop, the choice was to leave interpretation of the alternatives to a large extent to the students. For example, it matters whether the municipality subsidizes the bundling hub or not because that can severely influence the contribution of the alternatives to the criteria of the LSP. It matters even more as subsequent consolidated deliveries are carried out by a UCC operator and the LSP is delivering only from the supplier to the consolidation hub. In line with this situation, it matters what kind of stakeholder each group is. For example, is the municipality proactive or reactive, or does it take no role in the project at all? Additionally, depending on the project, other stakeholders could be added, for instance, a UCC operator.

ConCluSionS
Despite the negative impacts and, consequently, the high potential to make construction logistics more optimal for different stakeholders, construction logistics in urban areas is often neglected. In this paper, the MAMCA methodology is applied on a real construction project in a fictive setting with students to show how the objectives of stake- holders with different interests can be incorporated into the evaluation of alternatives. The alternatives are constructed in such a way that they can potentially contribute to more sustainable construction logistics. To what extent they contribute to the different objectives of the stakeholders becomes clear through analysis in a workshop. The MAMCA methodology allows incorporation of viewpoints of different stakeholders in the analysis. The methodology gives insight into the importance that stakeholders attach to their objectives, by allowing them to weigh criteria. This already leads to a better understanding by the stakeholders of where their priorities are, but more important, where those of the other stakeholders are. The same applies to the eventual evaluation of the different alternatives. In this way, complex decision-making processes in which different interests are involved are structured. The results structure the discussion and provide input for possible future implementation. The MAMCA software allows setting up a specific project that can be executed with actual stakeholders in a workshop. The MAMCA can be used to support real decisions. In this way, it can influence decisions that have to be made by certain stake holders such as the authorities. With the MAMCA software, the effectiveness of the proposed measures can be analyzed and taken into account. The MAMCA software furthermore allows for evaluations after or before but also to increase awareness among stakeholders. The latter was the aim of the workshop with the students in an educational setting. Involvement of students in this way helps them to take up various points of view and above all to clarify how difficult decisions in different fields such as transport are when diverging interests are involved. Similar workshops can be set up with the real stakeholders, allowing for further insights into the impact of the methodology.