Edinburgh Napier University

  Freight modelling and analysis has recently risen in importance. However although the concentration to date on specifically 'freight' vehicles and lorries has begun to cover the bulk of commodity tonnage flows, it has not properly addressed the mix of commercial, service and light goods movements that make up the bulk of the vehicle movements involved. The importance of these mixed light vehicle flows has been well established in freight policy considerations (Wigan 1978,1979), but the nature of the activities serviced by these movements has progressively changed, Lorry sizes have also increased substantially, so that the shipment of bulk tonnage involves fewer road vehicle movementsIn recent years there has been considerable speculation that the increases in the importance of the service sector and the growth of out-sourcing has led to increased LGV and LCV traffic in urban areas.

This paper addresses on-going research into the importance of the service sector in trip patterns and the associated, but not identical, traffic generation of light goods vehicles and light commercial vehicles (LGVs and LCVs). Despite the growing importance of this element of urban traffic the scale of activity, the problems caused and experienced and the nature of the operations are not well understood by researchers and policy makers. The overlaps between personal travel and commercial, service and light goods travel are particularly difficult to identify and handle as they can take place using either personal- or goods- labelled vehicles. The factors that are likely to result in the future growth of service (i.e. the family of commercial, service and light goods movement categories) trips in urban areas are discussed. The problems involved in researching service-related vehicle trips and developing suitable modelling approaches are also addressed.

Based on work carried out in the UK and Australia the paper addresses a range of service trip types, explores definitions and categories of service trips, comparing and contrasting these with goods trips. In some cases there is overlap and it is important to identify this in order to understand the emerging patterns of vehicle activity and operation.

There are typically difficulties in existing data in distinguishing between commercial movements and private movements of vans (LGVs and LCVs). However, it is important to do this in order to be able to collect data that may be used for modeling vehicle activity. The paper considers the transport modeling issues that arise from these developments, outlining possible modeling approaches and considering the data requirements, and the growing need to consider service industry activities as a distinct type of transport and activity process.