Proceedings of the 2019 Winter Simulation Conference
N. Mustafee, K.-H.G. Bae, S. Lazarova-Molnar, M. Rabe, C. Szabo, P. Haas, and Y.-J. Son, eds.
A GENERIC SIMULATION MODEL FOR SELECTING
FLEET SIZE IN SNOW PLOWING OPERATIONS
Yipeng Li Zhen Lei
Shuoyan Xu
Lingzi Wu
Simaan AbouRizk
Tae J. Kwon
Department of Civil and Environmental Engineering Department of Civil Engineering
University of Alberta University of New Brunswick
Edmonton, AB T6G 2W2, CANADA Fredericton, NB E3B 5A3, CANADA
ABSTRACT
Accumulated snow on roads poses a threat to traffic systems and rouses significant safety concerns. Snow
plowing is often used to recover roads in the event of heavy snow. Due to the unpredictability of weather
conditions, it is difficult to determine the overall performance of a certain truck fleet size, thus make it
challenging to estimate the number of snow plow trucks needed for a given highway area. The objective
of this research is to estimate the truck fleet performance under uncertain weather conditions, and to
provide decision support for selecting a reasonable fleet size. A generic simulation model is developed in
the Simphony.NET environment. Weather, road network, and truck speed data are entered as inputs, and
Monte Carlo simulation is used to generate random snow events to quantify the performance. A case
study is developed and presented to demonstrate the practicality and feasibility of the proposed model.
1 INTRODUCTION
Winter road maintenance is challenging for many northern countries (Shi 2010). Notably, Canada spends
around $1 billion dollars annually in winter road maintenance activities (Andrey et al. 2001). In practice,
snow plowing plays a significant role in winter road maintenance to remove as much loose snow on the
roads as possible, and to increase mobility and safety (Perrier et al. 2006; Usman et al. 2010). In order to
conduct snow plowing activities effectively, efforts have been made to improve planning efficiency. One
major aspect of optimizing snow plowing activities is the selection of the truck fleet size and the plowing
routes. In previous studies, snow plow routing optimization is considered as a Hierarchical Chinese
Postman Problem (HCPP) (Cabral et al. 2004; Ghiani and Improta 2000). The common solution for this
problem is to divide the area into several sectors and set one depot at each sector with an assigned truck
crew. When the snowstorm comes, trucks will depart from the depot to different road sections and return
to the same depot after all roads are cleaned. Due to the complexity of snow plowing operations, however,
the challenge is separating a large road network into small sectors and determining the crew size at each
depot (Stricker 1970). For example, the size of each sector will affect its crew size. Both the crew size and
the combination of roads within this sector must be considered when selecting the plowing route.
Additionally, uncertain weather conditions can stall this process because the snow coverage areas by
storms are unknown. As such, the roads need to be plowed, and the plowing route varies for each snow
event. Considering the random nature of weather events is necessary to resolve these problems. The
process of developing simulation models often requires repetitive efforts; a generic model is needed to
incorporate the planning process of snow plowing on various road networks. This paper therefore
proposes a generic model to simulate snow plowing processes under uncertain weather conditions. This
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