# Urban Transportation Network Design for Fresh Fruit and Vegetables Using GIS-The Case of Bangkok
## 1 Introduction  
The cold chain for the perishable products is defined as the entirety of supply chain operations and processes to ensure the temperature control within the predefined range [1]. The core function of the cold chain is to monitor the temperature in order to preserve the integrity and the quality of products and to guarantee the shelf life of goods [1]. However, transportation of perishable products and associated logistics operations pose many challenges for the cold chain [2]. Specifically, there exists the general requirement for keeping the products as safe as possible during transportation. In addition, products should be delivered within the predefined time window and, at the same time, meet the expected food quality. These factors complicate the design and planning of the fresh products distribution network [3]. In addition, owing to the increased consumer awareness and government regulations on food safety, several issues have continuously been addressed as the most important problems in the foodservice industry [4]. To cope with the rapidly growing population and the ever-increasing demand for high-quality fresh food, a more advanced transportation system for fresh food delivery is needed, particularly in urban areas [5]. In this context, Bangkok metropolitan, the urban agglomeration of Bangkok, is a most representative case where an advanced fresh food transportation network is urgently needed. Bangkok metropolitan includes Bangkok city and five surrounding provinces: Pathum Thani province (north of Bangkok), Nonthaburi province (northwest of Bangkok), Nakhon Pathom province (west of Bangkok), Samut Sakhon (southwest of Bangkok), and Samut Prakan (south of Bangkok). These areas around the Bangkok metropolitan have become some of the fastest growing metropolises in the world. The estimated population is 16.2 million as of 2019 [6]. Bangkok is the center of commerce and trade in Thailand and is also relied heavily upon by companies across the Indochina Peninsula; however, because of the high number of private vehicles and the insufficient supply of transportation services, the traffic congestion is a major problem. It was categorized as the most populous and traffic-congested city in the country by a landslide. This problem has huge impacts on businesses in the logistics and distribution. A high number of private vehicles and the insufficient supply of transportation services lead to congestion problems in Bangkok city [7]. In the global index compiled by TomTom traffic index, Bangkok has been ranked the second lowest in the world. During the morning rush hour, extra travel time increases by about 91%, while, during the evening rush hour, the increase in travel time amounts to 118% [8]. According to a recent survey of Ministry of Transport, the average speed of vehicles in the morning rush hour was 15 km per hour (km/h) [9]; however, the lowest average in the Southern Bangkok was recorded 10.1 km/h. The worst congestion road is mainly on Krung Thon Buri road in between Krung Thon Buri and Surasak intersection (5.1 km/h) [9]. Currently, Talaad Thai wholesale market is a major existing distribution center (DC) of fresh food in the central region of Thailand. It is also the biggest wholesale market in Southeast Asia. In addition, domestic consumption for fresh fruits and vegetables in Bangkok is mainly supported by Talaad Thai market. [5]. With an increase of urban freight movements, a single DC cannot efficiently handle the growing demand from customers while considering the distance, lead time, and internal operations in the warehouse, particularly when it comes to Just-In-Time (JIT) delivery of fresh products [10]. Therefore, a new transportation network design is necessary for fresh food distribution using multiple distribution centers (DCs) in Bangkok [10,11].