Road corridors contain countless sources of distraction, each carrying the potential to draw drivers’ eyes and minds off roads, thus increasing the risk of a crash. While the impact of billboards on driver distraction has received considerable attention, empirical data for other types of roadside advertising signs is very limited. Furthermore, the existing research examining other potential external sources of distraction is fragmentary, which makes it difficult to develop evidence-based road safety policies to mitigate risk. Therefore, the aim of this study was to conduct an exploratory review to ascertain and synthesise the available distraction-related literature for various types of roadside advertising signs (excluding billboards) and other potential external sources of distraction in the road corridor. Based on distraction-related theory and existing literature, 58 predefined categories of potential distraction sources were developed to guide an exploratory literature search using the Scopus database. Fourteen documents relating to external distraction sources were identified in the database search with a further five studies found using a backwards citation chaining search (N=19). However, no studies for non-billboard types of roadside advertising signs were found. Studies included those that investigated driver distraction in relation to construction zones, commercial logos contained within official traffic management Dynamic Message Signs (DMS) and service (logo) signs, drones, murals, roadside memorials and wind turbines. While one study investigated whether an external source of distraction can have a positive effect on driver behaviour, the remainder focused on the potential negative impacts on road safety of these sources of distraction. A key finding of the review is that crash risk increases when drivers continue to visually and cognitively engage with a source of distraction. Overall, the studies provide insights into the types of distractions that can be encountered in road corridors and the impact they can have on driver behaviour. However, more research is required before the mechanisms and pathways involved in these types of distractions can be effectively conceptualised, and thereby mitigated to reduce the burden of distraction risk and road trauma.@en

This paper proposes a conceptual framework to understand the relationship between roadside advertising signs, driver behaviour, and road safety outcomes. Roadside advertising signs are external distractions that may take a driver's attention away from safety-critical driving tasks, potentially increasing crash risk through driver distraction and inattention. Although studies report safety concerns, as a whole, the body of research in the field is inconclusive with inconsistent quality, making it difficult to draw firm conclusions. Definitive links between roadside advertising and road trauma are not yet evident, which has major consequences for road regulators' capacity to develop evidence-based policy to safely administer public roads. However, a lack of consistent evidence does not indicate an absence of risk but underscores its complexity. To address this problem, the Driver Behaviour and Roadside Advertising Conceptual Framework (DBRA framework) was developed to strategically investigate and conceptualise the phenomena of roadside advertising. A new term – “extended engagement” – has also been proposed to account for situations of prolonged attentional engagement with a roadside advertising sign. Further, it is posited that important variations in driving performance may be associated with a driver's extended engagement with a roadside advertising sign. Built on extant theories of driver behaviour and empirical research, the DBRA framework is designed to be a robust tool that encourages a common agenda for future roadside advertising research.@en

Driver inattention and distraction are recognised as two of the most critical factors for road safety worldwide. While roadside advertising is often identified as a potential source of distraction, it has received less attention compared to other types of distractions such as texting or calling while driving. Therefore, this study focused on the impact of roadside advertising signs on driver behaviour and road safety. To examine this, a theory-driven systematic literature review was undertaken. In total, 90 unique documents were identified and reviewed using the Task-Capability Interface (TCI) Model to explain the potential safety impact of roadside advertising. The findings confirmed that the TCI model is a useful tool for describing the relationship between roadside advertising and driver behaviour. From this perspective, roadside advertising signs can be considered environmental clutter, which adds additional demands to the driving task. In particular, roadside advertising signs impaired eye movement patterns of drivers. Additionally, it was demonstrated that the impact of roadside advertising on driving behaviour is greatly moderated by individual differences among drivers. Of great importance was that young drivers invest more attentional resources in interacting with roadside advertising, which suggests a lower capacity to discriminate between relevant and irrelevant driving information. Based on the available evidence, however, it is not possible to definitively conclude that there is a direct relationship between the driving behaviour changes attributed to roadside advertising and road crashes. Nonetheless, while most studies remain inconclusive, there is an emerging trend in the literature suggesting that roadside advertising can increase crash risk, particularly for those signs that have the capacity to frequently change (often referred to as digital billboards). Lastly, it is important to mention that most of the empirical studies undertaken to date feature strong methodological limitations. Consequently, there is an urgent need for more research in this area, given that roadside technology and the transport system are changing rapidly.@en