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This paper presents the findings of a stated preference research conducted in Tanzania (East Africa). The objective of the survey was to determine the relative importance as well as monetary values attached to freight transport quality attribute by shippers in this region. In-depth interviews with the logistic managers of companies that produce and ship goods were conducted. The freight transport quality attributes considered in this survey were flexibility, frequency, loss and damage, reliability, and transit time. The monetary values of these attributes have been computed as willingness to pay for their improvement as well as willingness to accept compensation for a decrease in their quality. The results show that shippers in this region consider travel time, loss and damage and frequency as the most important quality attributes. This may have relevant implications for the infrastructural transport policies to be implemented in the country. (C) 2011 Elsevier Ltd. All rights reserved.

The value of travel time savings (VTTS), is one of the key variables which are taken into account when several alternatives leading to different travel times are considered. In the case of households, VTTS is related to the monetary value that is attached to the possibility to save a determined amount of travel time that can be reallocated to other activities. In the case of public administrations, VTTS is one of the most important benefit categories aimed at justifying the investments in transport infrastructures that can allow people to save travel time. The relevance of VTTS has availed various economic studies displaying an analytical as well as an empirical framework both in the European Union and in North-American countries. The present paper aims at providing a meta-analysis of a selection of the studies related to the VTTS in passengers’ transport. It will introduce a brief history of meta-analysis (from its first applications in medical science and psychology to its recent use in spatial economics) and of the microeconomic models used in VTTS estimations. It will also identify the factors that are statistically relevant with respect to the VTTS and it will provide a meta-analytical estimation of the selected studies, with a particular emphasis on the similarities and on the differences among European and North-American studies.

The value of travel time savings (VTTS) has been investigated by transport economists since the mid‐1960s. Although the first two decades of research were mainly devoted to VTTS in passenger transport, since the mid‐1980s several studies have analysed the VTTS in freight transport from both a theoretical and an empirical viewpoint. The first part of the paper is devoted to a review of the proposed theoretical models for the value of freight travel time savings (VFTTS), and it discusses the issues arising from the use of different methods to collect empirical VFTTS estimates. The second part is based on a meta‐analysis of a sample of empirical VFTTS observations related to several European and North American countries. It is shown that both the per‐capita gross domestic product and the transport mode are statistically significant variables that can partially explain the variability in VFTTS estimates.