A Systematic Review of the Impact Overload on Road Pavement Batu City, Indonesia

Roads are land transportation infrastructure covering all parts of the road, including supporting buildings and equipment intended for traffic on the ground surface, above ground level, underground and/or water level, and above water level, except for railroads. and cable roads. Based on the Law of the Republic of Indonesia Number 38 of 2004, roads are classified based on their designation, encompassing public roads with functions categorized as arterial roads, collector roads, local roads, and environmental roads. Additionally, special roads are designated for specific purposes such as the distribution of goods and services, and are not intended for general traffic. According to Mohamed et al. [1] for the core transportation infrastructure, the road network has an intrinsic role in developing social and economic growth for each region and country. In addition, the existence of roads is also very important to support the growth of agriculture, culture, and other sectors [2]. Methodological gaps in addressing problems related to overloading, caused by heavy loads or an increase in the number of vehicles in several large cities in Indonesia, are often rooted in the lack of awareness among the public as road users. For instance, there is a significant gap in the predominant preference of the community for private vehicles over public transportation. These factors undoubtedly contribute to the heightened risk of premature damage to road pavements. Despite the government's efforts to enact regulations to tackle these issues, the cultural inclination in Indonesia remains resistant to swiftly comprehending and adhering to new regulations. Consequently, their implementation tends to be a time-consuming process.

Roads are currently often damaged in a relatively very short time (early damage), both roads that have just been built and roads that have just been repaired (overlay). According to Zainal et al. [3] basically, the road will experience a decrease in its structural quality by the increasing age of the road, especially if it is passed by vehicles with heavy loads and tends to exceed the provisions. According to Romadhoni et al. [4] the development and movement of people from one place to another in Indonesia is currently very high, making an efficient and well-maintained road network a very urgent need. Along with the increased movement of people and goods, increasing the concentration of people, especially in strategic areas, many vehicles also use these main roads over the planning limit [5]. In addition, there are physical and environmental developments of the metropolitan area [6], the distribution of the population that forms an urban sprawl result in unplanned and uncontrolled growth on the outskirts of the city, often characterized by low-density housing, single-use zoning, and increased reliance on private cars for transportation [7]. The population of Indonesia is increasing every year, reaching a notable growth rate of 1.13% in 2023 [8] is accompanied by a rising number of vehicles, reaching 153.40 million units [9]. Consequently, there is a substantial demand for road transportation. According to a study by Arifin [10], road construction is intended to provide services based on planned longevity. However, in reality, many sections experience a reduction in service life due to damage to road pavements. The most dominant factor causing rapid road damage is the excessive load received by road construction, exceeding the planned load.

Tourist mobility is a central concern in planning, urban spatial planning, and tourism activities, as well as in maintaining the quality of life for various groups involved. Tourist cities with high visitor potential must organize urban areas by adjusting road user patterns to prevent the blockage of movement circulation [11]. Tourists in Indonesia seek a more flexible mode of travel to accommodate their diverse travel needs, primarily opting for private vehicles [12]. The visiting pattern of tourists in Batu City shows a preference for private vehicles such as cars, motorcycles, or native city buses, as opposed to public transportation options like city buses or local public transport, resulting in an increased traffic load. The number of road users to and from the Batu City area continues to rise annually, leading to frequent vehicle congestion and traffic jams due to the growth of vehicles that is not proportionate to the existing lanes [13]. When examined from a mechanical perspective, the high volume of vehicles entering Batu City leads to the stress experienced by the road structure surpassing the planned capacity. This excess stress can be likened to the stress induced by overloading a vehicle axle, as it produces similar effects, notably resulting in permanent deformation of the road pavement structure. Consequently, the material is prone to cracking at an accelerated rate. The combination of wheel load and high tire pressure that is ignored can damage the surface layer and the overall pavement structure [14]. Regional policy formation greatly influences travel patterns in a city [15]. The local government of Kota Batu has developed and implemented regulations and official frameworks, such as Local Regulation No. 3 of 2011 regarding Permits for Public Transport Routes. This regulation supersedes Regional Regulation No. 10 of 2010, which pertains to Parking Fees on Public Road Sides. Additionally, odd-even rules have been applied to regulate vehicle traffic in Batu City. However, it is perceived that these regulations are still suboptimal in addressing traffic congestion and the growing number of excess vehicles in Batu City. Drawing insights from other tourist cities in Indonesia, such as Bogor, Bali, or Yogyakarta, an emphasis is placed on urban planning and traffic flow management to mitigate road-related issues. Potential strategies include increasing road capacity, redirecting traffic, improving and promoting public transport, and leveraging real-time traffic flow technology.

In connection with the advancement of vehicle overload theory, this research aims to provide an update through an analysis of the impact of overload resulting from the increasing number of vehicles in the research area, thereby generating comprehensive data. This data will serve as valuable input for road pavement life plan engineering to enhance its effectiveness in accommodating vehicular movements. Additionally, the research will formulate policies within a sustainable operational framework at the Batu City government level. These policies will be utilized for the planning and development of tourist areas, incorporating optimal city planning and traffic management practices.

Research on the impact of overloaded vehicles on road damage has been carried out and published in several journals over the last few years. The overload in question is a vehicle with a load that exceeds the Heaviest Axle Load (MST) limit which affects the value of the Equivalent Standard Axle Load (ESAL) and causes road damage to occur more quickly (cutting the actual road plan life) [3, 4, 16-18]. In operational terms, the damage factor represents the number of passes equivalent to one standard axle producing the same wear effect as one truck pass [19]. Adopting from these studies, a journal article on this topic will raise the issue of the effect of excess traffic/number of vehicles going in and out of Batu City on flexible pavement structures which have an impact on reducing the plan life of the road using case studies of tourism cities in Indonesia. The following questions aim to discuss and synthesize open issues relating to future research directions:

1. What are the main causes of the occurrence of the road load phenomenon related to the age of the road/pavement and the planning of the road network in Batu Tourism City?

2. What is the impact on the road/sidewalk planning scheme for Kota Wisata Batu due to the increasing number of vehicles using the road in the tourist city?

Specifically, this research will focus on qualitatively identifying the results of data analysis. The methods or approaches employed for data analysis encompass vehicle volume analysis, axle load analysis, the AASHTO method for calculating remaining pavement due to overload [16, 20], the linear regression method for comparing the equivalent value of passenger cars, and the IRI (International Roughness Index) method for assessing road surface conditions. The examination of causal factors will facilitate the determination of the relationship between vehicle growth and its impacts, aiming to propose an operational framework as the primary target for improving policies [21] and road planning in the current and future context of the study area.

The key findings supporting the research objectives indicate that the rise in the number of vehicles correlates with an escalation in the load exerted on road pavements. Consequently, the percentage of premature damage to road pavements also increases. Additionally, addressing the issue of overload can be mitigated or reduced by implementing policies in a phased manner, tailored to the specific conditions of the study area. The objective of specialization is to obtain the whole atlas of specialization chains (graphs) by assigning various types of members and joints to each available generalized chain (graphs) subject to the design requirements and design constraints specified above. Various types of theories, models, and policy implementations have been used to examine the impact of vehicle overload which will affect the pavement structure and the design life of the road itself. The literature review that has been reviewed conducts research based on problems that occur in each country or city with different pavement and environmental conditions so that the aspects discussed are quite broad but not far from the core/themes carried out in this study. The process of selecting and filtering articles, as illustrated in Figures 1 and 2, forms the foundation of the literature review in this research. It aims to contribute to an enhanced understanding of issues related to policies for excessive vehicle numbers, assumed to have similar implications as excess vehicle loads on road pavement. This undoubtedly influences the strength of the pavement structure and its overall lifespan.

Study literature review is carried out to obtain theoretical foundations that can be used to support solving problems that occur. In this case, the case study was conducted in Batu City, East Java, Indonesia. As a result of the city being known as one of the leading tourist cities because of its potential for extraordinary natural beauty, the growth of this area also encourages economic growth. The surge in tourists (inter-city and foreign) that occurs at any time can cause excessive road loads, the impact that will be felt if this problem continues is premature damage to road pavement causing congestion and even accidents. Seeing the existing conditions, the most efficient method is used, namely the analysis of the heaviest axle load by calculating each ESAL value but based on the number of vehicle movements in and out of Batu City, as well as the pavement assessment and the plan age of the road using the AASHTO method. After analyzing traffic and road pavement, the obtained results will serve as recommendations for policy formation. The proposed primary policy initiates with focus group discussions and the engagement of stakeholders in Batu City. Formulation follows the policy preparation guidelines set by the Indonesian Government. This policy includes regulations such as the expansion of main roads to facilitate vehicle movement, encouraging the shift from private vehicle use to public transportation in Batu City, expanding and developing terminals, and implementing traffic management measures. Therefore, establishing a policy to address the issue of excessive vehicle numbers in Batu City can serve as a reference for discussions, promoting the sustainability of street life in line with planning needs. This policy model can also be applied in similar cases in other areas. Future research should delve into vehicle load calculations, particularly involving the increasing number of motorized vehicles (two-wheeled), and explore more efficient structuring of tourist city areas.