The rapid growth of e-commerce has transformed urban freight systems, making last-mile delivery (LMD) a critical component of urban mobility with important implications for congestion, emissions, and operational efficiency. In response, several innovative solutions have been proposed, including urban consolidation centres, alternative delivery vehicles, etc. Among these, parcel lockers (PLs) have emerged as a promising option because they enable delivery consolidation, reduce failed delivery attempts, and improve service reliability.

Despite the growing literature on LMD innovations, limited attention has been devoted to the economic and investment dimensions of parcel locker deployment, especially across different territorial contexts. This gap is particularly relevant in the current policy framework, where European and national strategies increasingly promote transport decarbonisation and smart urban logistics. Understanding under which conditions parcel lockers represent a viable investment is therefore essential for evidence-based decision-making.

This study investigates PLs as an investment strategy in urban LMD systems, adopting a broader perspective that conceptualises them as decentralised micro-hubs or micro-warehouses for freight consolidation and temporary storage. Building on a structured literature review, the paper addresses two research questions: how freight micro-hubs affect the cost structure of urban LMD systems, and to what extent investments in parcel lockers improve delivery efficiency and reduce operational costs.

The analysis develops a cost-based evaluation framework using key parameters identified in the literature, including delivery costs, failed delivery rates, consolidation effects, and distance reduction. Focusing on Italy, the study compares metropolitan, medium-sized, and peripheral cities, and provides practical recommendations for logistics operators considering parcel locker investments.