Heterogeneity in urban freight policy impact: own-account agents in Rome’s LTZ, Working Paper SIET

Urban freight policy-making aims to improve the efficiency of freight movement in cities. Importantly, contemplated policies impact on complex pre-existent relationships among various agents operating in the distribution chain. The most relevant operators to study are: retailers, transport providers and own-account. There is a lack of knowledge concerning the specificities of these agent-types behaviour that calls for a more detailed analysis at the agent-specific level. This paper focuses on Urban Freight Transport (UFT) where an agent-specific policy analysis is carried out with specific attention to own account agents. Own account is, in fact, among the least studied agent-types in this context. This lack of attention is mainly due to the difficulty in acquiring data concerning their preferences and also to the widely accepted presumption concerning their relative inefficiency often giving rise to highly penalizing policies specifically aimed at this group. The empirical results reported are derived from a study conducted in the limited traffic zone (LTZ) in Rome's city centre in 2009. The analysis is based on a highly detailed and representative data set. This include both general information on the specific respondent involved along with company characteristics as well as stated ranking exercises (SRE) where interviewees are presented with alternative policy scenarios and asked to rank them according to their preference structure. The paper reports on the specific preference structure for own account operators. The paper proposes a systematic comparison, via WTP/WTA measures, between the potentially inaccurate estimates deriving from a simplistic analysis of preferences and those originating from an advanced treatment of preference heterogeneity. These considerations are prodromal to potentially distorted policy forecasts that, in turn, would be fed into micro simulation models to evaluate policy impacts. Various forms of heterogeneity are explored. The data allow the analysis, among other socioeconomic characteristics, of the impact that belonging to specific macro-freight-sectors has on the attributes used in the SRE. Furthermore, adopting a latent class (LC) specification, we test for the presence of respondent clusters in evaluating the policy mix considered for implementation. The paper addresses methodologically innovative issues; uses a new, detailed and significant data set; discusses a policy relevant issue and produces useful information from a policy-making perspective. The quantification of WTP and WTA measures for possible policies to be implemented provides an important benchmark both for policy makers as well as for researchers in this sector