Capturing Sustainability Goals in City Logistics: A Delphi Approach to Develop Sustainability Indicators

Purpose of this paper: ‘Sustainability’ as a phenomenon is difficult to define and sense (Meadows,1998). Sustainable city logistics is a concept with many subjective interpretations by different actors in the urban freight transport ecosystem (Behrends et al., 2008). Developing useful metrics to measure sustainability performance and impact in city logistics is challenging as there are many uncertainties and multiple stakeholders’ interests to consider. Selecting the indicators is also a complicated task because of the numerous variables used in literature and the variety of KPIs reported by logistics companies in their sustainability reports. Extant research studies have proposed different frameworks and indicators to assess sustainability in city logistics. However, the quality, practicality and applicability of the indicator vary. This is due to the absence of a holistic approach that engages both public and private stakeholders who can define sustainability goals for city logistics and develop the sustainability indicators accordingly. This study captures the sustainability goals in city logistics with consideration of both public and private stakeholders and proposes indicators to measure the sustainability performance of city logistics activities. Design/methodology/approach: The Delphi method was used in this study. A heterogeneous Delphi expert panel was formed with 50 city logistics experts in Europe. The participants included academic experts, local authorities, and logistics service providers identified from city logistics-related research projects in Europe. Using two rounds of Delphi survey questionnaires, qualitative and quantitative data were collected. A niche form of the “policy Delphi” was also incorporated in the data analysis, not only for gauging the consensus but also for eliciting the diverse views among the panel experts (Rayens and Hahn, 2000). Findings: The definition of ‘sustainable city logistics’ and different sustainability goals perceived by public and private stakeholders were captured. A list of 42 provisional indicators developed based on literature, sustainability reports and experts’ nominations were evaluated in terms of their relevance to the sustainable goals. Value: By engaging 50 experts from 22 different cities as a novel data corpus, this study extends the empirical observations to explore the priority of different sustainability goals, and subsequently to assess the relevance of indicators for measuring these sustainable goals. Radical and heterogenous ideas identified among experts during the process help to gain a richer and more balanced picture of sustainable city logistics from a multi-stakeholder perspective. The proposed ‘Define-Design-Develop-Deploy’ indicator development stage model in line with the design thinking for sustainability development has brought a new disciplinary perspective into the logistics research. Research limitations/implications: Radical and innovative ideas identified among experts during the three-round Delphi surveys help to gain a holistic understanding of sustainable city logistics from a multi-stakeholder perspective. Practical implications: The proposed sustainable city logistics indicators were developed by engaging experts from different cities with different expertise backgrounds. These indicators offer policymakers and practitioners a list of prioritised metrics aligning with policy agenda or business objectives.