European Transport / Trasporti Europei (2012) 50/XVII

This paper proposes a trip chain order model for simulating retailer restocking within urban and metropolitan area. It is part of the general modelling system developed by the authors for simulating urban freight demand which considers both demand and logistic sub-systems. The former allows us to obtain the freight Origin-Destination (OD) matrices in quantities and deliveries per transport service type, time slice and vehicle type. The latter allows us to obtain the vehicle OD matrices according to the journey characteristics (i.e. number and sequence of delivery points) in order to restock economic activities located within the study area. This approach, known in literature as tour-based approach, aims at reproducing the choice structure of the restocking process and the sequence of delivery points (stops) for vehicle journeys, considering dependences existing among subsequent trips of the same journey. It implies that each destination zone to be delivered is chosen depending on the previous and the next destination ones. The logistic subsystem of the proposed modelling system can be divided in two parts: the first which defines the trip chain order (i.e. the number of deliveries made during a tour); the second one which considers the choice of the stop locations. This paper focuses on the specification and calibration of a trip chain order model using data collected in the city centre of Rome.

In this paper, a modelling framework to complete the recent scientific works on urban goods modelling is proposed. More precisely, we introduce a substitution procedure that estimates the number of trips and the corresponding travelled distances for shopping drive, home delivery and reception points' strategies. Moreover, an appraisal of scenarios is proposed in order to study how these three new forms of proximity delivery services impact on the overall urban goods movement distribution. Starting from four extreme situations, we introduce more realistic scenarios in order to find a suitable combination of delivery strategies. All the scenarios are simulated using the proposed framework, and the main traffic issues related to e-commerce distribution channel are discussed. The best realistic combination promotes the joint usage of home deliveries and proximity reception points and allows a reduction of about 13% of the road occupancy rates in urban areas.

Rail is today a minimally used modality in urban freight distribution. To reap the benefits of this more sustainable transport mode a few experiences in Europe have attempted to introduce innovative freight distribution schemes where rail is used. One of such schemes uses rail for the urban penetration leg. After having been consolidated in a centre located outside the urban area, goods are transported by shuttle trains to a centre located inside the central area (the multi-modal urban distribution centre – MUDC) and there are transferred to low-pollution road vehicles to reach their final destination. Other schemes use tramways. The paper provides a review of rail-based schemes which have been introduced in European cities. An in-depth assessment is provided of the scheme based on the use of a MUDC. The case study relates to the distribution of fish food in Rome. The environmental and energy benefits obtainable from the shift from the current road-only scheme to the MUDC scheme are estimated in physical and monetary units. An estimate is provided of the maximum public contribution that would still make the scheme beneficial for society as a whole, obtained as the difference between the social costs of the road-only scheme and those of the MUDC scheme. Also, an assessment is provided of the profitability of the scheme from the operators‟ viewpoint.

Manufacturing firms buy transport services with the aim of minimizing their total logistics cost. There is a large amount of literature analyzing how shippers value the various characteristics of a transport service, mostly performed by collecting stated-preference data and estimating discrete choice models. Most of the empirical studies specify the deterministic part of the utility functions as linear in the observed attributes. This implicitly constrains the characteristics of the analyzed transport service to be perfect substitutes, and to have a constant substitutability ratio. Such an assumption is inconsistent with the standard microeconomic theory, typically assuming inputs’ decreasing marginal productivity, and may not be realistic. The paper tests the linearity assumption for freight rate, travel time, probability of having damaged and lost freight, frequency, flexibility, mode and punctuality on a sample of Italian small- and medium-sized manufacturing enterprises (SME). Our findings suggest that the linearity-in-the-attributes assumption should be rejected and that the marginal impact on the utility-of-profit of the attributes is not constant. More specifically travel time and freight rate produce decreasing marginal reductions of the utility-of-profit; while safety (percentage of not damaged or lost shipments) and punctuality (percentage of shipments on time) are responsible for increasing marginal contributions to the utility-of-profit. The substitutability ratios between (a) freight rate and loss and damage, (b) freight rate and travel time, (c) freight rate and punctuality, (d) travel time and damage and loss and (e) travel time and punctuality are estimated and found not constant. Finally, it is found that the willingness to pay for the qualitative attributes obtained with a linearly specified model tend to be overestimated.

There is scope for applying experimental economics in transport and logistics analysis. Experimental economics is a set of techniques for gathering (and analysing) data by inducing people (through specific rewards) to act as economic agents and observing the choices they then make in experimental situations. These experiments often involve interactions between the respondents, possibly in a market setting, and this can be applied in transport to study for instance shipper – carrier interaction. Various subfields of experimental economics that might be relevant for transport and logistics research are described. We also review past applications of experimental economics in transport and logistics and work out some ideas for future applications.