Impact of Variable Travel Time on the Solution of Vehicle Routing Problem: A Case Study of Bangkok

Abstract

In the logistics industry, it is essential to have optimized vehicle routes for cost-effectiveness and customer satisfaction. However, most conventional studies on vehicle routing problem (VRP) do not consider the variation in travel time, leading to nonoptimal routes. This study shows the importance of variation in travel time for different times of the day and different days of the week by comparing the optimization results of vehicle routes for constant travel time and variable travel time. Two different scenarios were considered for Bangkok city, Case-1, where customers are scattered across the city, while Case-2, where customers are concentrated on a small area. It was concluded that up to 27.59% error in travel time could be obtained with an average of 12% for Case-1. At the same time, a maximum 30.85% error in travel time can be obtained with an average of 7% for Case-2. Therefore, it is necessary to consider time-dependent travel time in urban logistics route planning in Bangkok. This study also put forward a method to collect travel time data of different origin-destination pairs for different times of the day and different days of the week that can be used by any logistics company.