Effects of multipurpose shopping trips on retail store location in a duopoly

Models for retail store location typically assume that consumers make single purpose trips. However, frequently, consumers purchase more than one product during the same trip. This is the first attempt to propose including multipurpose trips in models locating commercial facilities selling non-essential products. We model and analyze the case in which two firms sell one product or type of products each. Consumers buy one, both, or none, depending on the utility they obtain. We solve 1000 instances and report the results, which indicate that firms significantly benefit from taking into account multipurpose trips when locating their stores. Based on the difficulty to solve one version of the problem, we also derive an efficient heuristic algorithm for the solution and test its performance.