# The Application of Augmented Reality in the Automotive Industry: A Systematic Literature Review
## 1 Introduction  
In many industries, implementing modern technologies brings success in the tough global market. It propels a company's innovativeness forward and can even lower production expenses and maximize profits. Automotive manufacturers have always remained at the forefront in taking advantage of the latest technological advancements. Thus, the automotive industry has experienced a significant development, mainly due to the adoption of new advanced technological improvements such as virtual mock-up and prototyping, advanced manufacturing techniques based on sophisticated robotic systems, automated vehicle safety and user-friendly interfaces for improving driving experience. In recent years, many automotive manufacturers have developed a keen interest in augmented reality (AR), mainly due to its accessibility and potential for generating innovative solutions. AR is a form of human machine interaction (HMI) in which virtual components are inserted and superimposed on the real world, creating the illusion of an 'enriched' reality. It allows users to obtain certain information they need about some aspects or procedures directly in the working environment [1] and it has the potential to enrich a person's sensory perception [2]. Based on [PERSON]'s definition of a reality-virtuality continuum [3], AR represents a component part of mixed reality (MR), which is the merging of the real and virtual worlds. [PERSON]'s concept of a reality-virtuality continuum is exemplified for the automotive industry in Figure 1. The applications of AR range from industrial to everyday life activities, in various domains, like manufacturing, robotics, healthcare, education, military, entertainment and so on. There are several extensive studies that address the implications and impact of AR on industry, as well as the challenges and directions of development in this field [4; 5; 6; 7; 8; 9]. AR provides promising new possibilities in almost every area of the automotive industry due to its potential as an interactive and intuitive interface. The usage of AR in the automotive industry has been explored through various platforms. For instance, AR can substantially improve the user experience with head-up displays (HUDs). HUDs are display systems adapted from military aviation [10] to convey visual information in the driver' field of vision. They are see-through devices designed to present various real-time essential information in order to increase safety. There are two ways provided through HUDs: adding information into the environment or highlighting some elements already present in the environment [11]. One such interesting solution is to overlay a video stream over the car in front of the driver, where you can see what is in front of it [12]. AR contributes to many other aspects of the automotive industry, such as maintenance, repairing, diagnostics, inspection or training [1]. AR technology has also begun to be used as a marketing tool so that customers can interactively customize their car before ordering [13; 14]. Spot welding inspection through projector-based spatial AR [15; 16], tracking some parts of a vehicle using handheld devices [17] or performing maintenance procedures using head-mounted displays (HMDs) are some examples of using AR in various ways and through various platforms. This human-centered technology has proven to be useful for operators and workers in the area of car production, but also for drivers in order to improve certain characteristics related to driving activity. The benefits of AR were demonstrated through major collaborative projects such as ARVIKA, ARTESAS, EFA2014, AVILUS, EGYPT [18]. The goal of this study is to make a contribution to the current research by providing a cohesive view of systems using AR in a field that evolves significantly from year to year. This paper fills an important gap in the automotive research field and allows understanding on how AR technology was applied in this industry, what its added value is and what the challenges and trends are.