4c4d urban freight transportation, challenges, failures and successes positioning paper

Urban Freight Transportation: Challenges, Failures and Successes Goos Kant Tilburg University, Faculty of Economics and Business Administration, Box 90153, 5000 LE Tilburg, the Netherlands g.kant@uvt.nl Hans Quak TU Delft, Transport and Logistics, Jaffalaan 5, 2628 BX Delft, the Netherlands, and TNO, Mobility, P.O. Box 49, 2600 AA Delft, the Netherlands h.j.quak@tudelft.nl, and hans.quak@tno.nl RenĂŠ Peeters Tilburg University, Faculty of Economics and Business Administration, Box 90153, 5000 LE Tilburg, the Netherlands m.j.p.peeters@uvt.nl Tom van Woensel TU Eindhoven, Industrial Engineering & Innovation Sciences, P.O. Box 513, 5600 MB Eindhoven, the Netherlands T.v.Woensel@tue.nl

Abstract In this paper; we present the challenges, failures and successes, leading to lessons learned and our vision on urban freight transportation. This positioning paper is partially based on earlier work of Quak (2008), in which he analyzed 106 unique urban freight transport initiatives, undertaken between 1998 and 2006. This review is extended with all known more recent material. We identify the different involved stakeholders with their interests. The evaluation of projects and lessons learned are distinguished in policy, logistics and technology initiatives. Based on this we present a vision for urban freight transportation.

1. Introduction The OECD (Organisation for Economic Co-operation and Development) Working Group on Urban Freight Logistics [35] defines urban goods transport as the delivery of goods in urban areas, including the reverse flow of waste. Freight transportation of goods (both forward flows and reverse flows) is therefore a key activity within urban areas. Many large cities face significant challenges related to the congestion and pollution generated by the number of vehicles that need to travel within urban areas. These vehicles are one of the main causes of undesired environmental side-effects but their role is fundamental to the efficient functioning of cities as they satisfy many of the transportation needs that occur on a day-today basis. Urban transportation includes not only the transportation of goods. A significant proportion is attributed to the transportation of people. These latter are not only residents and shoppers, but also service and other vehicle trips for commercial purposes, which are essential to the urban functioning. Within the European Community, all large (and many small) cities have managed the transportation of people by developing public transportation networks that are generally integrated (but could still be improved). Freight transportation is completely different and is very immature. By comparison, the urban transportation of 1

goods is almost completely managed by private Logistics Service Providers (LSPs) and/or shippers who manage their own transportation requirements without any coordination, leading to many unnecessary movements (from a city perspective) of underutilized vehicles in congested areas.

Obviously, many stakeholders are involved with urban freight transport, each having their own, sometimes conflicting, stakes in urban freight transport. Specifically, authorities, carriers, receivers, residents, shippers and traffic participants all make use of the same scarce resources available in the urban areas. This makes it difficult to develop sustainable urban freight transport solutions, as a wide variety of (often conflicting) problem perceptions and solutions exist [6]. This, of course, has a significant impact on urban traffic and new sound logistics solutions are required to better manage the flow of goods into, through, and out of, urban areas. Urban goods transport thus emphasizes the need for a systemic view of the issues related to urban freight movements.

The already significant volume of freight vehicles in urban areas is steadily growing. An important driver for this is the worldwide trend towards urbanization, leading to larger cities and vacating the countryside. Within the OECD countries, this evolution is very clear: in 1950, 50% of the population lived in cities, 77% in 2000 and it is expected that by 2020, this will rise to 85% [34]. Currently, 80% of the European population lives in urban areas, while about 85% of the EU's GDP is generated in cities [19,52]. The demand for urban freight transport is clearly growing, and will continue to do so. In Europe, "transport is the most problematic emitting sector, with upward emission trends" [20]. Between 1990 and 2007, CO2 emissions from transport rose by 29%. Road transport accounts for a sizable portion of CO2 transport related emissions, nearly 73% in 2000 [23]. Within road transport related CO2 emissions, urban traffic accounts for 40% of CO2 emissions, and 70% of emissions of other air pollutants [19]. In terms of traffic congestion, every year nearly 100 billion Euros, or 1% of the EU's GDP, are lost to the European economy as a result of this phenomenon [25]. The number of road traffic accidents in towns and cities is also growing each year: one in three fatal accidents happen in urban areas [25]. In cities, large trucks and vulnerable road users (cyclists and pedestrians) share the same infrastructure. Furthermore, just over 41 million Europeans are exposed to excessive noise from road traffic alone in the largest European cities (The European Environment Agency (EEA)). An important contemporary challenge for large cities is to improve the air quality: to satisfy the European norms for NOx, cities have to improve their air quality considerable. High concentrations of NOx and PM10 have negative consequences for the residents’ health.

The majority of goods in urban areas are delivered via road haulage. It is startling to note that, on average, 24% of goods vehicles in Europe operate empty. Smaller vehicles have an average load capacity of only 57%. Drastically reducing these inefficiencies is a major challenge for European policy-makers and private industries. A 30% increase in efficiency would create an estimated economic value of â‚Ź22 billion for the Transportation Industry.

The private and public sector are increasingly challenged by these urban growth figures. This demonstrates the need for better control of urban freight transportation in order to reduce its impact on adverse living conditions in cities.

This positioning paper on Urban Freight Transportation will outline the different challenges, successes and failures seen in this exciting environment. The remainder of the paper is structured as follows. In Section 2 we identify the different stakeholders with their interests.

In Section 3 we review the known urban freight transport projects, distinguished in policy,

2

logistics and technology driven initiatives. In Section 4 we describe the lessons learned. We conclude in Section 5 with a vision for urban freight transportation.

2. The different stakeholders in Urban Freight Transportation Stakeholders involved in urban freight transport differ in their urban freight transport interests, their resources and possibilities, as well as their power (of decision). They have also different means available, in order to safeguard their interests. Since the focus is on freight, we do not explicitly talk about some other, important, stakeholders in the city, such as inhabitants, etc. In all cases, (local) government is concerned with the stakes of this type of stakeholders.

Government Governmental stakeholders are roughly divided into higher and local authorities. Higher governments tend to deal with urban freight transport problems as local issues, and are therefore usually not directly involved in it. Interestingly, higher governments take measures with a significant impact on local issues, like air quality. Examples are the EURO-norms for truck engines, which have resulted in a considerable decrease in local pollutants, but also (in the Dutch context) the implementation of road / congestion charging schemes. Higher government (national and, more and more, the EU) determines the playing field of all private stakeholders: regulations on truck sizes, working hours, infrastructure, etc. Local authorities have the autonomy to determine the context for urban freight transport for their specific city. This implies that the context in which carriers are active with their urban freight transport operations differs not only per country, but also even per city (or, in the extreme but realistic case, even per street, see e.g. [16].

In general, (local) government looks after the interests of the impactees, since these are their ‘voters’ in elections. Impactees are these involved parties that notice the impacts of urban freight transport, both positive and negative impacts [36]. We discern three groups among the impactees: the residents (who live in the city centers), the shopping public (a collective term including the stakeholders that make use of the facilities in city centers, such as shops, restaurants and pubs, theaters etc.) and traffic participants (those actors that are confronted with urban freight transport, for example passenger transport for commuter traffic). Moreover, these impactees usually have little means to look after their interests, except for complaining at the (local) government.

Increasingly, the environmental impacts of transportation, city accessibility and increasing congestion are continuing concerns in government’s urban transport policy reflections.

Unfortunately, little cooperation or harmonization exists between urban freight policies making, which makes these regulations quite disordered. Two often observed policies are setting time-windows and imposing vehicle restrictions. Time windows primarily improve the shopping climate and increase the traffic safety for pedestrians and cyclists. Vehicle restrictions mainly focus on the protection of buildings and infrastructure and the reduction of emissions and noise. Higher governments also implement sustainability initiatives like EURO norms, road pricing, which have an impact in general, including at urban freight distribution.

In [16] it is argued that most authorities plan and regulate urban freight transport similar as they did over two decades ago. These regulations aim at restricting the urban freight traffic as much as possible (see also [1]). Clearly, this standstill means that government is ignoring the increased possibilities due to the recent ICT developments and the changing urban environments. For example, over the last three decades, retail organizations evolved

3

considerably [22]. Many retailers introduced Just-In-Time store deliveries. This evolution of retail store distribution shows that, contrary to governmental policy making, urban freight transportation has taken advantage of the possibilities from new technologies and that it is organized very different from some decades ago [44].

Shippers, Carriers and Receivers The relationships between carriers, shippers and receivers seem straightforward: the receiver (e.g. a store) orders goods at a supplier, the supplier hires a carrier to transport the goods to the store and then the carrier delivers the goods. These groups however consist of very heterogenic stakeholders. For example, the receivers, or retailers, differ considerably; and with that, their stakes in urban freight transport issues as well. But this process, the responsibilities and delivery conditions, vary over the urban freight deliveries.

Shippers and receivers There is a strong interaction between the receiver (e.g. a store) and the shipper; they can even belong to the same retailer organization. From a shipper perspective, we usually do not see a role for urban freight transportation for those manufacturers of goods, who do not have own stores. Ordering of goods can be a push-process from the shipper, or a pullprocess from the receiver. In general it is a mix, depending on product category, and whether it is a regular product or a promotion. The receiver’s interest is especially in minimizing the perceived inconvenience caused by trucks and in creating a nice shopping environment. Since this receiver does not feel responsible for the transport, and does not pay for it directly (the transport price is hidden in the price it pays for the goods), he sees less direct opportunities to participate in or to initiate any initiative in urban freight transport. For receivers that are part of a large retail chain the situation is different. In this case, all deliveries are usually coordinated by the retailer’s headquarters, which acts as shipper in this case. The result is that the retail chain is responsible for the transport and not the receiver. Retail chains are focused on a supply chain optimization, rather than a transport or sustainability optimization. As a result, their supply chain strategy of Just-InTime store deliveries leads to an increase of frequency for delivering the goods and, hence, to a less sustainable solution.

Carriers Quak [41] distinguishes between regional carriers, functional carriers and generalists. The regional carriers often cooperate with other regional carriers in a network (for example, TransMission in the Netherlands). These regional carriers usually have a depot in the region in which they are active. As a consequence, it takes only a limited time to reach cities in this region. The regional carriers see local time-windows (and other restrictions) as an opportunity, since their vehicle route planning and their vehicle fleet is adapted to the local situation. Whereas, these local restrictions are a threat for other carriers that have to deal with longer distances to cities and several local regulations, and cannot easily adapt to various local situations. The major gains in vehicle utilization, from a city perspective, can be achieved by aiming at generalists and private carriers (own transport). The network carriers (e.g. TNT and DHL) and regional specialist already bundle goods and enter cities with full trucks. The degree of bundling for private carriers and generalists is probably considerably lower (although accurate data is lacking, which is a problem in itself for urban freight transport).

3. Review of urban freight projects In this section, we review the large amount of city logistics initiatives and the more limited amount of research projects executed over the past years. The importance of city logistic in

4

general and urban freight transport in particular has been receiving increasing attention throughout the years. As a consequence, a number of private and public sector initiatives have been proposed (An overview and classification of these projects is presented in [5]).

However, a limited amount of scientific research focused on the issue of better transportation management. Next to solutions initiated solely by (local) authorities and companies, there is a huge number of initiatives involving several stakeholders and combining two or all solution directions (i.e. technology, logistics and policy). These initiatives are system initiatives, since these initiatives require changes in more than one part of the urban freight transport system.

In his dissertation [40] Quak presented 106 unique Urban Freight Transport initiatives, undertaken between 1998 and 2006. This review from 2008 is extended with recent material and initiatives including the City Logistics conferences of 2007, 2009 en 2011, the relevant scientific publications since 2007 (based on Scopus-searches), several EU-projects, and recent Dutch initiatives (from the Ambassador Urban Freight Transport or other sources, such as Transumo). The European research projects included in this extended review are: Bestufs, Cityfreight, Citylog (and Citymove), Citymobil, Civitas, Fideus, Freilot, Sugar, Turblog and Urban Track, as well as experience of researchers in the urban freight transport field.

We distinguish between three different solution directions to improve urban freight transportation: policy, logistics and technology. Usually (local) authorities use policy initiatives in order to regulate urban freight transport operations. Most technological initiatives aim at reducing nuisance without changing the actual operations. Logistical solutions include the organization of transport and logistics within one company and also supply chain collaboration or other forms of collaboration. Technology focuses more on technological advances, e.g. electrical vehicles. We use this classification for reviewing the variety in initiatives aiming to improve urban freight transport. Note that, in practice, many initiatives are (or should be) combinations of these three solution directions. In many cases the different directions have to be included in a solution to make it work (e.g. new technologies require changes in policies and make a different logistical concept possible).

3.1 Policy Policy solutions are initiated by (local) government. We argue that government has several means available in realizing its urban freight transport policies; i.e. regulating, coordinating, facilitating, and stimulating. Most policy initiatives are in the area of regulation.

Using regulation, local authorities aim at changing carriers’ operations in order to become more sustainable (or at least cause less nuisance) by obliging legislation. We distinguish several different regulation initiatives, with usually also varying sustainability objectives: vehicle restrictions, vehicle utilization controls, low emission zones, time-access windows, and dedicated infrastructure. Usually these initiatives are not used in isolation, but to make other solution directions work (for example, a low emission zone forces carriers to use cleaner vehicles). Licensing and regulation initiatives are quite common in European countries (see [35]).

Local authorities use vehicle restrictions to improve traffic safety, reduce traffic problems, and protect buildings and infrastructure from being damaged. Besides, these restrictions are implemented to reduce nuisance caused by large trucks and so to improve quality of life in cities (e.g. reduction in visual nuisance and improvement in (perceived) traffic safety). As a result of vehicle restrictions, carriers use more small trucks in most cases to deliver a similar

5

amount as with larger trucks. Therefore, many vehicle restrictions result in a negative impact on the accessibility of cities, on the environment, and on the logistical costs. The main objective of vehicle utilization controls is to decrease the number of vehicles entering the city due to stimulating consolidation outside the city center in order to increase the vehicle load utilization. The governmental objective corresponding to this type of initiative is improving city accessibility and livability in cities. Although the results are positive, vehicle load factor controls are extremely hard to enforce. Local authorities use low emission zones (or environmental zones) to improve local air quality in cities by excluding pollutant trucks from entering city (centers), i.e. local pollutants, such as PM and NOx. Only trucks that fulfill engine requirements are allowed in the low emission zone. Obviously, this initiative type results in a decrease of local pollutants emitted, but notice that for PM and NOx also other sources are relevant (see for example [46]). Low emission zones might increase cost for carriers depending on the number of zones and the vehicle replacement cycle. Timewindows restrict access to areas, usually the city center, during periods of the day, in which residents are not bothered and shopping public is not hindered. Time-windows might improve the attractiveness of a city center and the traffic safety, these improvements go at the expense of the logistical costs and the environment (in pollutant emissions). Local authorities use dedicated infrastructure to oblige large vehicles to use only specific streets.

The idea to force vehicles to use specific routes is to increase traffic safety and quality of life in an urban area (i.e. on the rest of the network) and to preserve infrastructure that was not designed for heavy vehicles. These initiatives can either originate from an attempt to ban or restrict urban freight operations or they could make urban freight transport more efficient.

Especially the initiatives from the last case show positive results on accessibility and transport efficiency.

The key action to coordinate urban freight transport is road pricing. The reason for road pricing initiatives is to make the scarce road capacity subject to market functioning with the idea to better spread traffic volume over time in order to reduce congestion as well as the traffic related emissions. Well-known road pricing examples are found in London (congestion charge) and Stockholm. Road pricing aims at all traffic participants and not only at urban freight transport. Whether road pricing changes the actual urban freight transport operations depends on the type of carrier and actor that determines the delivery time (see [28, 42]).

Authorities can also play a role in facilitating urban freight transport. Initiatives focusing on the locations for (un)loading in the (dense) city centers are often used. Parking and unloading initiatives are used to solve two types of problems: problems that are caused by the scarcity of available loading areas in crowded city centers and accessibility problems that are caused by unloading vehicles e.g. double parked vehicles that are unloading result in traffic problems. Most parking and unloading initiatives focus on creation (e.g. using bus bays) or reservation of dedicated unloading areas. This is relatively easy and not expensive.

Many of these initiatives are implemented in practice. Authorities also play a role in the facilitation of city distribution centers (CDC’s, see later). Other examples of facilitating urban freight transport are making off-peak deliveries possible. This requires the change of current time-window restrictions. Obviously, logistics changes are equally necessary to make deliveries during off-peak periods, but without facilitating authorities, these adapted logistics will not work in practice (see [3, 28]).

We see different ways to stimulate more sustainable urban freight transport. The EU provides research and pilot subsidies (see the huge number of EU projects on the subject of urban freight transport over the last decade) in their FP6 and FP7 programs as well as in

6

some Interreg projects. Another example, is the Award Urban Freight Transport given in the Netherlands (award stedelijke distribitie), awarded by the Ambassador Urban Freight Transport in December 2009, to the combined contribution of Utrecht – including the Beer Boat and the Cargohopper of Hoek Transport, see the (Dutch-written) document ‘Stedelijke Distributie’ Logistiek, februari 2010 for all contributions. Finally, another example of the (local) authority in a stimulating role can be found in the ‘proeftuinen’ (experimental projects with electric transport) in Amsterdam.

3.2 Logistics Next to policy initiatives coming from government, shippers, carriers and receivers also initiate actions towards improving urban freight transport. There are several logistics initiatives in urban freight transport literature. The first type contains initiatives in which carriers cooperate: i.e. carrier cooperation, see [15]. The main aim of carrier cooperation initiatives, that require competitors to cooperate, is to improve urban freight deliveries’ efficiency. This means that unit cost will decrease and more products or services can be offered. As a side effect, city congestion and pollutant emissions are reduced. Other drivers for carrier cooperation in urban freight transport are improving customer service, overcoming legal and regulatory barriers and accessing new technology. Carriers can cooperate in different ways, e.g. by consolidating goods at one’s premises or by using a neutral carrier (for example by shared participation) in order to prevent two half-filled vehicles to visit one street. Furthermore collaboration offers the potential of joint purchases.

Another way to improve urban freight transport’s sustainability is to use more environmentally friendly modes to actually transport the goods. Intermodal urban freight transport initiatives try to reorganize transport by using non-road modes that produce fewer pollutant emissions. However, in most cities rail or water networks are usually not dense enough to deliver a considerable part of the urban freight volume (apart from the obvious exceptions such as Venice). Quite often these initiatives fail due to organizational issues, extra costs for handling and the lack of network-density. In studies, some concepts are described that combine passenger and freight transport (e.g. trains, trams and metros), but these systems are not brought in practice. Some small scale applications of intermodal transport exist, such as waterborne or rail concepts in city distribution, e.g.: Parcel services (DHL boat) in Amsterdam, MokumMariteam in Amsterdam (construction materials), beer and beverage deliveries in Utrecht (the beer boat), The Monoprix example in France (see [18]), The Cargotram in Dresden, etc. Intermodal urban freight transport is only feasible in specific circumstances and for a limited marginal part of the total urban freight transport volume. This is thus not a generic sustainable solution for urban freight transport issues.

We observe three different system initiatives: the development and use of standard load units (e.g. city containers), the development and use of urban consolidation centers, and the development of underground logistics systems. The idea for a standard load-unit for city distribution is based on the success of the sea container. Standardized load unit initiatives are mainly an enabler for the success of other initiative types that depend on efficient transfer of goods, e.g. consolidation center initiatives. Urban consolidation centers are typical city logistics initiatives (see for example [49]). The rationale for consolidation centers is to divide the freight transport in two parts: the part inside the city and the part outside the city. City Logistics models have been proposed in the academic literature [48, 49, 50].

Most of these models mainly focused on passenger transport within urban areas. Modeling the demand of goods is important for urban transport. A number of demand models have been proposed for evaluating the demand for freight movements within urban areas (see [24] for a review). The decisions with respect to planning of CDCs in terms of number,

7

location and characteristics have not been extensively studied. In this context, we mention the work of [44].

Single-tiered city logistics systems operate only one level of consolidation-distribution activities, distribution routes starting at a CDC and delivering the loads directly to the citizens. The city logistics projects initially undertaken in Europe and Japan were based on the single-tiered concept, mostly involving a single CDC and a limited number of shippers and carriers. Different business models and strategies were tested (e.g. [51, 54]). A solution methodology for single-tiered systems is proposed [12]. More advanced systems are emerging that handle the complexities of large cities. The majority of such systems have a two-tiered structure. Loads are first consolidated at a CDC into large vehicles, which bring them to a smaller CDC-like facility “close” to the city center. This makes up the first tier of the system. Loads are then transferred to smaller vehicles, appropriate for city center activities, which then deliver to the citizens, thus making up the second tier of the system.

The work of [12], proposes a solution methodology for the daily planning for two-tiered systems. The business models for these city distribution centers (CDC’s) are examined in more detail in [45].

3.3 Technology Next, we see the technological initiatives. These can be pushed or stimulated by (vehicle) manufacturers or authorities, but also by shippers or carriers. We make a distinction between vehicle-technology innovations and initiatives related to ICT and ITS applications in urban freight transport. Most technological vehicle innovations reduce some of the nuisance caused by vehicles, such as noise, emissions and even safety. Industrial technological vehicle innovations make trucks cleaner. Also regulations stimulate cleaner technologies, for example Euro-regulations on motor and permitted (local) pollutants have huge impact on the amount of local pollutants emitted. Next electric trucks, hybrid propulsion, CNG trucks are experimented with in urban areas. Many initiatives could be reported in this initiative type, but most of these innovations seem to be implanted rather than described in urban freight transport literature. Several technological solutions are tested in EU projects, for example the Fideus-project provides a set of vehicle solutions for urban freight transport.

One (successful) example of a technical solution was already mentioned under ‘facilitating’ of authorities: the Piek-program in the Netherlands. Technological solutions made it possible to develop quiet material, i.e. trucks, trailers and roll containers.

We see several initiatives in which (usually at a limited scale at this moment) electric vehicles are used for urban freight transport. The use of these vehicles often requires also changes in the logistics as a decoupling point nearby the city is required because of the limited radius of action of the electronic vehicles. In the Netherlands, we see some examples of the use of new vehicle technology (see also [41]): electric vehicles (see 4C4D partners Cornelissen, TNT with electric transport in London, as well as the ‘proeftuin project’ with electric vehicles of Peter Appel; the use of LHVs (longer and/or heavier vehicles) that are decoupled at the city border (e.g. Ahold); and the use of CNG vehicles (e.g. Ahold and Cornelissen). Although elelctric transport is often mentioned as a solution for urban freight transport (silent vehicles and no local emissions), there are hardly (large scale) experiments with this type of urban freight transport, since reliable vehicles only recently come available.

One of the few pilot projects that were fully evaluated is published in [33].

There are different initiatives that are based on ICT and ITS developments outside the urban freight transport. Many (city logistics) academics fall into the VRP-field. Vehicle routing

8

improvements are an example of technological solutions based on IT. Typical city problems, i.e. congestion, result in an infeasible vehicle planning. The main idea of vehicle routing improvement initiatives is to better incorporate real-life problems and so to reduce the number of vehicle kilometers travelled and the penalty costs. Therefore, these initiatives show positive results on carriers’ costs and on the environment. Most of the reviewed initiatives are not tested in practice, but especially by simulation. An example of a current project that aims at developing special route planning software for city logistics is CityLog (see www.city-log.eu). In the EU-project Freilot ITS services for more efficient urban freight transport are developed (see www.freilot.eu).

4. Lessons learned Given the large number of urban freight transport initiatives in the recent past, it is essential to learn from these when starting or considering new initiatives. First of all, it is observed that researcher-initiated initiatives are hardly implemented in practice. Apparently there is a serious lack in (direct) interaction between academia and the carriers. Besides, many academic articles focuses on modeling city logistics. Although, modeling good models are necessary to evaluate solutions, they do not contribute to bringing initiatives in practice. A recent review (see [2]) gives an overview of different modeling approaches, different actors involved and different modeling objectives. Recently, in city logistics literature agent-based modeling is becoming more popular (see for example proceedings of City Logistics VII, 2011).

We observe there is a clear gap in the scientific literature and the real practices operated in urban freight transportation planning. As the number of related industry-based projects and initiatives is increasing, there is a necessity to carry out sound scientific research in this area which addresses the actual base problem faced by those involved in these activities. This necessity stems from the fact and the need that scientific research can easily be disseminated between interested parties. In this section, we draw some overall conclusions, based on the different elements presented. Obviously, these three solution methods should be combined (as much as possible), whereas the strengthen each other and are often necessary to be implemented successfully in practice. One of the examples of where a good mix of all three solution directions led to an improvement of the urban freight transport operations comes from the Netherlands; it is called off-hour distribution, which means distribution in the margins of the day. Technological solutions made it possible to develop quiet material, i.e. trucks, trailers and roll containers (see Piek-project). Policy solutions made it possible to deliver during the early morning outside the time windows (and before the morning peak congestion hours). This change in policy made it reasonable for carriers to invest in quiet material; if the policy would not have been changed there would be no reason to invest, although the nuisance would decrease, since these investments would not result in any gains for the carriers. And finally logistical solutions made it possible to rearrange transport activities to the early morning (e.g. drivers now have keys of stores, warehouse activities are at different time to prepare the truck loads earlier, etc). By combining the three solution directions the FTL (full truckload) deliveries of supermarket chains in the Netherlands became more sustainable in all aspects: improved traffic safety (since fewer persons are around when the truck unloads), fewer emissions (no congestion), no increase in nuisance, and less logistics cost. So the first lesson is to consider all solution directions, and not to isolate them.

4.1 Policy Governmental policies often result in a deterioration of the carriers’ logistical performance.

Many policy actions strongly depend on regulations and sanctions to force carriers to cooperate. However, many regulations, like vehicle restrictions and time-window access, result in a negative impact on the accessibility of cities, on the environment, and on the

9

logistical costs. For road pricing, parking and unloading, and some dedicated infrastructure initiatives, carriers and local authorities share the same problem perception, i.e. congestion or reduced city accessibility. If this is the case the initiative’s results appear to be more positive. So enforcement is not the only success factor. Policy initiatives show that knowledge-levels of government of logistical operations are usually limited. On the other hand, carriers also lack knowledge about the sustainability objective of initiatives. The lack of interaction between local authorities and carriers prevents an increase in understanding of each other’s issues. We noticed that local authorities define an initiative’s action area, which does not correspond to the larger geographical area in which the carriers’ logistical operations take place. At this moment there is little cooperation nor harmonization between the different local authorities, which makes urban freight transport regulations quite disordered. A complicating factor within a local authority is that urban freight transport policy is often divided over several departments, like the environmental, the traffic and transport, and the economic affairs department. In some initiatives the local authorities also play a more private role, e.g. they offer or finance transport services from the city distribution center (CDC) or manage the CDC (see e.g. [38]).

Although city distribution centers seem very appealing, there are almost no examples running a successful business without financial support from governments. For example, Browne et al. [9] found that of the approximately 200 planned or realized city consolidation center schemes in the nineties in Germany at most five are actually operating in 2005. In many studies, the carrier participation is estimated higher than it turned out to be in practice. This implies less bundling of goods and fewer scale advantages than planned for the participating carriers. From the different consolidation center initiatives we learn that many carriers consider supporting policy measures as a way for local authorities to keep the non-viable center alive, instead of the consolidation center as a way to be able to deal with the (usually restricting) policy measures, such as time-windows. Currently, (huge) subsidies are necessary to operate urban consolidation centers. So there should be enough societal gains (e.g. less pollution) to justify for the subsidies. These gains are not always clear.

Overall, consolidation centers seem to be most feasible, if feasible at all, for historical cities that have restrictive and inhibitive conditions for urban freight transportation anyway, next to potential governmental restrictions. Recent studies conform these results [53].

An important question is why the physical infrastructure initiatives do not come from private actors. Is this because of the high initial costs only, or are these initiatives financially not feasible on the long term? Therefore, the high uncertainties of the results form a barrier. On the other hand these initiatives show more potential to increase sustainability than any other discussed initiative category. Public private partnerships (PPP) are mentioned in several physical infrastructure initiatives as potential success factor (see e.g. [7, 16, 26, 27, 30]).

4.2 Logistics Logistics initiatives are coming from shippers, carriers and receivers Carrier cooperation initiatives mainly focus on improvements in the logistical operations and have only an economic incentive rather than a sustainable incentive. Based on the limited number of implemented initiatives in practice, a real incentive for carriers appears to be lacking. This type of initiative asks for unanimity between the logistical operations of more than one carrier. In [31] it is argued that this type of cooperation, due to costs for reaching agreement, can be quite costly from a business perspective, which is the opposite of an incentive. One of the few-implemented initiatives, the cooperation in the German city Kassel, was not successful in the end [32]. A survey of Cruijssen et al. [14] revealed that one

10

of the main impediments to cooperation of LSPs is the size of their company. The market of LSPs is very fragmented which makes cooperation only practical for the larger firms. To make it more likely for carrier cooperation initiatives to be successfully implemented there should be a clear problem and a sound business case. Further potential success factors are: making sure a company does not loose its identity, include social costs in the initiative, support from the public sector, make all gains clearly visible, distribute them fairly and be as transparent as possible, and appeal to an organization’s social and environmental reputation [15]. In academic literature (especially by Operation Research researchers) theoretical models have been studied widely. These theoretical results are often positive, however in practice these systems are (at this moment) often too complex to actually start (see for example the satellite-system discussed by Crainic et al. [13]).

To actually improve urban freight transport, carrier co-operation is expected to increase in the near future (see also the Capgemini report [10]). These urban (or regional) bundling activities could, but do not necessarily should, be supported by different (and innovative) forms of city distribution centers (CDC’s). The way of co-operation and exact use of a CDC is dependent on the efficiency of the logistic processes, the characteristics of the city, the regulations, and the goods and involved stakeholders. However, in all cases, the described success factors, both quantitative and qualitative play a major role to co-operate between carriers. So, more research and experience is required in the quantitative and qualitative roles of co-operation, like gain sharing and not losing the identity. Binnenstadservice is an example of a CDC that aims at the receivers in a city. This concept is examined in the Transumo-project ‘Transition towards more sustainable urban freight transport’. The results show some positive local results (see e.g. [46]. However, especially financial issues remain to be resolved to really call this a success (see also [45] on the business model of city distribution and Binnenstadservice).

The amount of retailer initiatives initiated and documented in the reviewed literature, is limited. Retailers and local shops try to attract the consumers to buy goods in the most convenient way. For consumers, sustainability is of growing concern in their selection process, though they are less willing to pay extra. This challenges the retailer to continuously improve their supply chain, without increasing the overall costs. For the involved environmental pressure of the retailer, we have to consider the replenishment transports. In general the execution of those transports is outsourced to logistic service providers (LSP’s).

LSP’s have the lead in combining different retailers as much as possible in one truck. Of course, this should be acceptable for the retailer. In general, food retailers and big beverage suppliers accept this less. Here, the qualitative aspects of competition and not losing the identity seem to be more important than the quantitative aspects of sharing benefits.

Very interesting from a retailer perspective is whether replenishment and delivery strategies of their products can take sustainability into account. Research in this area is focused on combining replenishment with transportation planning and is called inventory routing. A lot of research is done in this area, in particular for the bulk industry (like oil and gas), but very limited in the retail industry. Retailers nowadays in general have fixed delivery patterns and routing schemes for a certain period, rather than applying dynamic delivery. Also for replenishment days there is hardly any alignment currently between stores with the same specific brands or products to make a joined delivery possible at all. Hence the challenge for the retailers and urban shops is given the context of local government rules and policies, and the capabilities of the logistic service providers, to optimize their own logistics. This means, optimizing their drop size, delivery sequence and delivery time, while improving their sustainability by collaborative planning.

11

4.3 Technology There are different initiatives that are based on ICT and ITS developments, also outside the urban freight transport. The main idea of vehicle routing improvement initiatives is to better incorporate real-life problems and by using the newest optimization technology reduce the number of kilometers travelled and the related emission. The initiatives in this direction are implemented by commercial VRP-software programs (like trip planning and advanced planning systems) and show positive results on carriers’ costs and on the environment.

Some of these initiatives do not try to improve the planning, but use real time information to find the best possible solution after an event or congestion actually occurs. This is a crucial element to improve the service (meeting agreed service time agreements). ICT also play an important role to have a transparent and open overview of the transportation, when multiple partners are involved. This is crucial when costs need to be shared in a fair way among the partners, and when partners are dependent on each other (e.g., a company executes the distribution for a partner).

The technological vehicle innovation initiatives that were found (in academic literature) show positive environmental results. The advantage is that this type of initiatives usually does not require serious changes in urban freight operations, however the investment costs are considerably high for carriers. Therefore, there could be an active role for governments to stimulate (or at least facilitate) investments by subsidies or other advantages for clean trucks from some licensing and regulation initiatives. The use of these vehicles often requires also changes in the logistics, whereas a decoupling point nearby the city is required because of the limited radius of action of the electric vehicles. Important lessons are that many special urban freight transport vehicles, that are developed with special dimensions (or other special issues) are usually not used much in practice. The problem is that these vehicles can only be used for the city, and that they have disadvantages for other usage (e.g. limited capacity). Many carriers do not spend enough time in cities (due to limited volume, time-window restrictions, or customer requirements), to reach the break-even point for such the investment in special urban freight trucks. So, vehicles should also be designed in order to operate outside the city centre.

Finally, most technical solutions require investments, usually from carriers. Carriers are more likely to be willing to invest if they can have some advantages themselves, think about longer time-windows, being allowed to enter a low emission zone, etc. In other words, policy solutions could stimulate or facilitate the actually bring technical solutions in practice.

5. A vision for Urban Freight Transportation The previous sections show the need for a systemic view for efficient urban freight transportation systems, resulting in a sustainable distribution network. Significant gains can be achieved through better coordination and consolidation of the urban freight distribution resulting in fewer vehicles in cities, better utilization of these vehicles and less emissions.

Coordination reflects the fact that shippers, LSPs and retailers are coordinated and consider the activities of each other when planning their own activities. Consolidation leads to combining different loads and carriers into the same vehicles. In order to achieve these goals, new organizational urban freight models considering policy, logistics and technology are necessary.

Given the different elements of policy, logistics and technology, our vision is that sustainable solutions should consider these three aspects in a balanced way (instead of considering

12

them separately). The initiatives and lessons learned show strong relations between them, and new initiatives in research and practice ideally consider these three aspects.

Policy

Technology

Logistics

Clearly, the development of a global solution to urban freight transport needs to incorporate promising new concepts and solutions (over the three aspects),, considering the characteristics of cities, and should lead also to a powerful definition of the role of governmental regulation. In the public sector, just as in the private sector, accurate modeling of operations and logistics functions is a necessary precondition to effective operational planning and control for society as a whole. Public sector managers play a key role in determining and nd regulating societal externalities and standards for environmental quality. Policy conclusions and regulatory policies based on inaccurate modeling affect the entire economy. Since policy has a fundamental impact on the costs of logistics activities of firms, irms, the private sector will of course be affected as noted above. We argue that the same tools that have brought so many gains to the private sector are equally critical in the public sector. Indeed, the consequences of inaccuracy or incomplete modeling in the public sector can be even more significant than in the private sector as they frequently give rise to policy conclusions and regulatory policies that can affect an entire economy and not just a single firm. This is perhaps nowhere more evident than in the area of transportation policies where many local authorities do not propose extensive and well-motivated well motivated freight transport policies [1]. Besides, most urban freight transport regulations or initiatives are not evaluated on their effects in practice.

Through the use of coordination and consolidation, a more efficient (both in terms of logistical costs and environmental impacts) urban transportation system will be achieved.

Typically, the private sector focuses on controlling the internal costs, and iss less preoccupied with the external issues of their operations (emissions, noise, accidents, etc.). However, controlling the internal costs may also have positive impacts on the external costs related to urban environments. The ultimate urban transportation system improvement targets are reducing both internal costs and external costs caused by the urban freight transport activities.

Most solutions for LSPs in urban freight transportation are in co-operation co operation or collaboration.

Important success criteria are hard constraints like revenue or profit improvement and a fair sharing model of the costs. However, as reflected in the lessons learned, also soft criteria like not losing the identity and finding an eligible partner are crucial success factors.

Successful current co-operations operations between LSPs will act as an example for new initiatives, 13

and to extend the existing ones, for example, by exchanging trailers (which can be from long and heavy vehicle) between trucks of different LSPs and different customers. In this way expensive cross-docking costs and time can be avoided. Important element in this is an urban network design problem. Having vehicles and trucks coming from outside the urban area and going directly to the final citizen is undesirable, as it leads to increased freight movements within the city. Locations and times for the rendezvous between trucks and green vehicles have to be set. This synchronization is challenging since routes include several intermediate points. Therefore, research in success criteria of collaboration between multiple LSPs is important in several ways: first of all the qualitative (not losing identity and finding an eligible partner) and quantitative aspects (fair way of cost sharing) is important.

But also business models for setting up possible co-operations by introducing City Distribution Centers or efficient ways of cross-docking or exchanging resources are crucial for success.

From a more academic perspective: each LSP has its own logistics services with some residual capacities and a set of transportation requests. In this context, also combinations of combining the delivery of the incoming flow of goods with the pickup of the outgoing flow (backhauling) should be taken into account. Thus, the same vehicle can be sent in the urban area to deliver goods to citizens and to pickup waste or recycling materials from the same set of citizens or from new citizens. The first issue is to determine allocations between transportation requests and transportation offers. Physical constraints as well as time requirements have to be taken into account and transportation chains involving different LSPs could be considered. The second issue is how the benefits generated by the collaboration can be fairly divided between the alliance members. This is a key concern since the solutions provided by the allocation system could be quite different from those obtained by individual optimization. Moreover, LSPs will share transportation requests if and only if this leads to improved solutions from their point of view, without losing their identity.

The last mile of the retail supply chain up to the shelf represents both the highest supply chain cost and the biggest citizen service risk. An essential objective for retailers is to provide a high availability of their products at low operational costs. This ultimately challenges retailers to formulate good plans, well executed. Retailers are often located relatively close to each other, e.g. in the same shopping street. In almost all cases, retailers act independently of each other. Specifically, it would be interesting from a transport consolidation point of view, to coordinate the inventory ordering process among different retailers. Delivery schedules need to be adapted among different retailers employing different inventory policies.

Our discussed vision is in line with the Future Supply Chain 2016 report [10] in which is argued that the future supply chain architecture should anticipate to new collaborative models for city distribution that need to be applied in urban infrastructures. The key element in their concept lies in merging different streams into one infrastructure via implementing city hubs, with a collaborative cross-dock operation. The final solution will be applied differently per shipment category. This latter implies consolidation of different delivery streams, (e.g. all for the same shopper) via city hubs. For this, retailers have to consider the replenishment strategies, jointly maximizing the resource utilization, leading to efficient deliveries into the urban stores.

Finally, note that it is important that a good co-operation is required between academia and industry. For the qualitative and quantitative aspects of collaboration between LSPs more fundamental research is required, e.g., by investigating both market and literature. For a

14

successful implementation, and related validation and valorization, a strong link with the industry (both local governments, carriers and retailers) is necessary. They have the experience and arguments why certain initiatives do or do not work in practice. For the proposed initiatives and projects, the underlying business model is also crucial.

Governments might support new projects initially, if the investment costs are too high for new logistic concepts. But on the long run it should be clear that new collaboration and cooperation initiatives should have a commercial incentive from the involved partners to be successful in the future. Therefore the involved investment costs and benefits for involved parties should be transformed to a related business model, where the corresponding management structure and responsibilities are organized.

References [1] Allen, J., S. Anderson, M. Browne, and P. Jones (2000). A framework for considering policies to encourage sustainable urban freight traffic and good /service flows.

Transport Studies Group, University of Westminster, London.

[2] Anand, N., H. Quak, R. van Duin and L. Tavasszy (2011). City logistics modeling efforts: trends and gaps – a review. in E. Taniguchi and R. G. Thompson (eds.), City Logistics VII, 108-124, City Logistics proceedings, Kyoto.

[3] BCI and Kirkman (2008). Distribution to Supermarkets in the Evening and Early Morning. SenterNovem, The Hague.

[4] Benjelloun A., and T.G. Crainic (2009). Trends, Challenges and Perspectives in City Logistics. Buletinul AGIR nr. 4/2009.

[5] Benjelloun A., T.G. Crainic and Y. Bigras (2009). Toward a Taxonomy of City Logistics Projects. Procedia - Social and Behavioral Sciences 2(3), 6217--6228, Elsevier.

[6] Browne, M. and J. Allen (1999). The impact of sustainability policies on urban freight transport and logistics systems, in H. Meermans, E. Van de Voorde, and W. Winkelmans (eds.), 8th World Conference on Transport Research (WCTR), Volume 1 Transport Modes and Systems, 505-518, Elsevier, Antwerp.

[7] Browne, M., T. Nemoto, J. Visser, and T. Whiteing (2004). Urban freight movements and public-private partnerships, in E. Taniguchi and R.G. Thompson (eds.), Logistics Systems for Sustainable Cities, proceedings of the 3rd international conference on City Logistics, 17-36, Elsevier, Amsterdam.

[8] Browne, M., j. Allen, S. Andersen and A. Woodburn (2006). Urban freight consolidation centers. In Taniguchi E. and R.G. Thompson, Recent advances in city logistics, 253-265, Elsevier, Amsterdam.

[9] Browne, M., M. Sweet, A. Woodburn, and J. Allen (2005b). Urban freight consolidation centres - final report. Transport Studies Group, University of Westminster, London.

[10] Capgemini, Future Supply Chain 2016 (2011). Global Commerce Initiative, Report.

[11] Crainic, T.G., N. Ricciardi, G. Storchi (2009). Models for Evaluating and Planning City Logistics Transportation Systems. Transportation science,43 (4), 432-454.

[12] Crainic, T.G., N. Ricciardi, G. Storchi (2009). Advanced freight transportation systems for congested urban areas. Transportation Research Part C: Emerging Technologies,12(2), 119-137.

[13] Crainic, T.G., G. Perboli, S. Mancini and R. Tadei (2010). Two-Echelon Vehicle Routing Problem: A satellite location analysis. Procedia - Social and Behavioral Sciences, 2 (3), pp. 5944-5955.

[14] Cruijssen, F., M. Cools, and W. Dullaert (2007). Horizontal Cooperation in Logistics: Opportunities and impediments, Transportation Research Part E 43, 129 – 142.

[15] Cruijssen, F., W. Dullaert, H. Fleuren (2007). Horizontal cooperation in Transport and Logistics: A Literature Review. Transportation Journal, 22 – 39.

15

[16] [17]

[18]

[19]

[20] [21] [22] [23]

[24] [25]

[26] [27]

[28]

[29]

[30]

[31]

[32]

Dablanc, L. (2007). Goods transport in large European cities: Difficult to organize, difficult to modernize. Transportation Research Part A, 41 (3), 280-285.

Demir, E., Bektas, T., Laporte, G. 2010. A comparative analysis of several vehicle emission models for freight transportation. CORMSIS Technical Report, University of Southampton, Southampton, UK. Delaitre , L. and C. De Barbeyrac (2011). Improve an urban distribution centre, the French case of Samada Monoprix. in E. Taniguchi and R. G. Thompson (eds.), City Logistics VII, 873-894, City Logistics proceedings, Kyoto.

EUROPA Commission takes action to make urban travel greener, better organised and more user-friendly http://europa.eu/rapid/pressReleasesAction.do?reference=IP/09/1379 last accessed October 2010.

European Environment Agency (2009). Greenhouse gas emission trends and projections in Europe. Nr. 9/2009.

Facanha, C., and A. Horvath (2007) Evaluation of life cycle air emission factors for freight transportation. Environmental Science & Technology, 41: 7138–7144.

Fernie, J., F. Pfab, and C. Marchant (2000). Retail grocery logistics in the UK. International Journal of Logistics Management, 11 (2), 83-90.

Fuglestvedt J., T. Berntsen, G. Myhre, K. Rypdal, and R. B. Skeie (2008). Climate forcing from the transport sectors. Proceedings of the National Academy of Sciences of the United States of America, 105(2208), 454-458.

Gentile G., and D. Vigo (2007). Movement generation and trip distribution for freight demand modeling applied to city logistics. Technical Report, Unversita di Bologna.

GREEN PAPER (2007). Towards a new culture for urban mobility, http://ec.europa.eu/transport/clean/green_paper_urban_transport/doc/2007_09_ 25_gp_urban_mobility_en.pdf. Commission of the European Communities.

Hesse, M. (2004). Logistics and Freight Transport Policy in Urban Areas: A Case Study of Berlin-Brandenburg/Germany. European Planning Studies, 12 (7), 1035-1053.

Heuer, J.P. (2004). Summary of the OECD Report ‘Delivering the Goods – 21ste Century Challenges to Urban Goods Transport’, in E. Taniguchi and R.G. Thompson (eds.), Logistics Systems for Sustainable Cities, proceedings of the 3rd international conference on City Logistics, 431-440, Elsevier, Madeira, Portugal.

Holguin-Veras, J. (2010). The truth, the myths and the possible in freight road pricing in congested urban areas. Procedia - Social and Behavioral Sciences, 2 (3), pp. 63666377 Holguin-Veras, J., R. Marquis and M. Brom (2011). Economic Impacts of Staffed and Unassisted Off-Hour Deliveries in New York City. in E. Taniguchi and R. G. Thompson (eds.), City Logistics VII, 39-54, City Logistics proceedings, Kyoto.

Ishida, H. E. Taniguchi, T. Hyodo, A. Sasaki, H. Ando, and K. Ikeda (2006). Experiment report transportation demand management experiment in Akihabara 2004, in E. Taniguchi and R.G. Thompson (eds.), Recent advances in city logistics: proceedings of the 4th international conference on city logistics, 389-400, Elsevier, Amsterdam.

Kawamura, K. and Y. Lu (2006). Effectiveness and feasibility of innovative freight strategies for the U.S. urban areas, in E. Taniguchi and R. G. Thompson (eds.), Recent advances in city logistics: proceedings of the 4th international conference on city logistics, 269-282, Elsevier, Amsterdam.

Koehler, U. (2004). New ideas for the city-logistics project in Kassel, in E. Taniguchi and R. G. Thompson (eds.), Logistics Systems for Sustainable Cities, proceedings of the 3rd international conference on City Logistics, 321-332, Elsevier, Amsterdam.

16

[33]

[34] [35] [36] [37] [38] [39]

[40] [41]

[42]

[43]

[44]

[45]

[46]

[47] [48] [49] [50] [51] [52]

Leonardi, J., M. Browne, and J. Allen (2011). Before-after assessment of a logistics trial with clean urban freight vehicles: a case study in London. in E. Taniguchi and R. G. Thompson (eds.), City Logistics VII, 158-170, City Logistics proceedings, Kyoto.

OECD. Delivering the goods: 21st century challenges to urban goods transport.

Organisation for Economic Co-Operation and Development, OECD Publishing.

OECD (2003). Delivering the goods - 21st century challenges to urban goods transport. OECD working group on urban freight logistics, Paris.

Ogden, K. W. (1992). Urban Goods Movement: A Guide to Policy and Planning.

Ashgate, Aldershot.

Parmenter, D. (2010). Key Performance Indicators: Developing, implementing, and using winning KPIs. John Wiley & Sons, 2nd edition, Hoboken, NJ. Poel, W. van der(2000). Leyden Car(e) Free, an integral approach to a better environment in an old city centre. Gemeente Leiden, Leiden.

Potter, A., R. Mason, and C. Lalwani (2007). Analysis of factory gate pricing in the UK grocery supply chain. International Journal of Retail & Distribution Management, 35 (10), 821-834.

Quak, H.J. (2008). PhD dissertation, Sustainability of Urban Freight Transport: Retail Distribution and Local Regulations in Cities. Rotterdam Erasmus University.

Quak, H.J. (2011). Improving Urban Freight Transport Sustainability by Carriers. in E. Taniguchi and R. G. Thompson (eds.), City Logistics VII, 171-186, City Logistics proceedings, Kyoto.

Quak, H.J. and R. van Duin (2010). The influence of road pricing on physical distribution in urban areas. Procedia - Social and Behavioral Sciences, 2 (3), pp.

6141-6153.

Quak, H. J., J. Van Nunen, and N. Agatz (2009). Customized policies for sustainable urban distribution, in E. Taniguchi and R. G. Thompson (eds.), City Logistics V, 335350, NOVA Science Publisher, New York.

Quak, H.J. and R. de Koster (2009). Delivering goods in urban areas: How to deal with urban policy restrictions and the environment? Transportation Science, 43(2), 211-227.

Quak H.J. and L.A. Tavasszy (2011, forthcoming). Customized solutions for sustainable city logistics; The viability of urban freight consolidation centres, in: J. van Nunen, P. Rietveld en P. Huijbregts (eds.) Transitions towards sustainable mobility, Springer, Berlin.

Rooijen, T Van and H.J. Quak (2010). Local impacts of a new urban consolidation centre – the case of Binnenstadservice.nl. Procedia - Social and Behavioral Sciences, 2 (3), pp. 5967-5979.

Taniguchi, E., T. Yamada and D. Tamagawa (1999). Modeling advanced routing and scheduling of urban pickup/delivery trucks. World Congress on ITS, Toronto, Canada Taniguchi, E., R.G. Thompson, T. Yamada and R. van Duin (2001). City Logistics: Network Modeling and intelligent transport systems, Pergamon, Elsever Science.

Taniguchi, E., R. E. C. M. van der Heijden (2000). An evaluation methodology for city logistics. Transport Rev. 20(1) 65–90.

Taniguchi, E., R. G. Thompson (2002). Modeling city logistics. Transportation Res. Record 1790 45–51.

Thompson, R. G., E. Taniguchi (2001). City logistics and transportation. Handbook of Logistics and Supply-Chain Management. Elsevier, Amsterdam, 393–405.

URBACT. http://urbact.eu/en/projects/metropolitan-governance/egtc/our-project/ last accessed October 2010.

17

[53]

[54]

Verlinde, S., C. Macheris, and F. Witlox (2011). How to consolidate urban flows of goods without setting up an urban consolidation center? in E. Taniguchi and R. G. Thompson (eds.), City Logistics VII, 795-813, City Logistics proceedings, Kyoto.

Visser, J., A. van Binsbergen, T. Nemoto. 1999. Urban freight transport policy and planning. E. Taniguchi, R. G. Thompson, eds. City Logist. I, 1st Internat. Conf. City Logist. Institute of Systems Science Research, Kyoto, Japan, 39–69.

18