lockbox signed to any location? CASE 6.4 Removing Snow in Montreal Based on: Campbell, J., and Langevin, A."The snow Disposal Assignment Problem Journal of the Operational Research Society, 1995, pp. 919-929 Montreal and Snow removal and disposal are important and expensive activities in by plowing many northern cities. While snow can be cleared from streets and sidewalks and shoveling, in prolonged subfreezing temperatures, the resulting banks of accumu- lated snow can impede pedestrian and vehicular traffic and must be removed. several To allow timely removal and of snow, city is divided each sector. In sectors, and snow removal operations are carried out concurrently in (for Montreal, accumulated is onto and hauled to disposal reasons, example, rivers, quarries, sewer chutes, surface holding areas). For contractual site each sector may be assigned to only a single disposal site. (However, each disposal fa receive from multiple sectors.) The different types of disposal sites can commodate different amounts of snow due to either the physical size of the disposal cility or environmental restrictions on the amount of snow (often contaminated by five and icing chemicals) that be dumped into rivers. The annual capacities for different snow sites can (in 1000s of meters): are given in following table Disposal Site Capacity 350 250 500 400 200