Recurring patterns of commercial vehicle movements in urban areas: the Parma case study

Urban freight transportation plays a critical role in ensuring the competitiveness and development of urban economies. Even if congestion levels rise, recent trends in transportation service requirements, such as just-in-time systems, contribute to an increasing proportion of commercial Vehicle Kilometers Travelled (VKT) in urban areas. The necessary high frequency of replenishment operations, along with the reluctance of end-users (retailers, private customers, etc.) to receive shipments outside given time-windows, make the distribution operations less efficient. Starting from the definition of recurring tours types in urban operations, the paper focuses on their application on a real case: Parma, Italy, and the mutual interrelation among typical features: the urban environment, end-users typical behaviours, operational issues, and road traffic congestion. As binding constraints, such as tour length and favourite time slots for deliveries, affect tours design and management, the paper aims at assessing the impact of such constraints and possible consequences on the distribution process efficiency. The paper outlines relevant implications for data collection efforts: no realistic statements about the properties of urban freight tours in relation to their efficiency and contribution to VKT can be made unless there is disaggregated information on tour routing constraints and their temporal dimension, which suggests a revision of usual methods for truck trips generation based on commodity flows. Moreover, the application of the modeling approach to a city with a premium built environment such as that of Parma, can be considered as a step forward compared to those examples applied to less complex urban patterns.