Size and Density Economies in Refuse Collection

The focus of the paper is to analyze the costs of solid waste collection by applying a well-behaved multiproduct cost function model to a sample of more than 500 Italian municipalities. Beyond shedding light on the presence and on the extent of size (or scale) economies, our aim is to investigate in depth the issue of economies of density, which is still an underexplored topic in the literature. Our cost function specification, by being able to estimate several measures of density economies (such as output density economies, vertical density economies and horizontal density economies), allows to capture the impact of different urbanization models on the costs of refuse collection and disposal. The results of the estimates highlight the presence of output density economies as well as horizontal density economies. Conversely, there is significant and robust evidence of the existence of vertical density diseconomies, which suggests that congestion problems in densely populated councils are severely affecting garbage collection costs. Finally, there is evidence of diseconomies of size, which suggests that aggregating the refusal collection operations of several municipalities would not bring savings in the average costs.