Passenger presence and driver-passenger interaction effects on distraction and road safety: an interaction-driven narrative review

Driver distraction is a significant factor in global road traffic injuries and crashes. Technological distractions have been well studied, but social distractions caused by passenger interaction have not been sufficiently studied despite their impact on driving behaviors and safety. This narrative review synthesizes evidence on the impact of passenger presence and driver-passenger interactions on distraction, driving performance, crash risk, and injury severity, with a particular focus on driver and passenger demographics. Following PRISMA 2009 guidelines, 58 peer-reviewed studies published between 2002 and 2025 were identified from major academic databases and narratively synthesized due to substantial heterogeneity in study designs and outcome measures. Passenger effects depend heavily on context. Young drivers show both high crash risk and risky behavior when accompanied by peer passengers because of social facilitation and active interaction, whereas mature adult passengers are generally protective. Adult and older adult drivers gain supervisory support from the passenger presence, but the risk increase with multiple or child passengers under high caregiving demands. Active driver-passenger interaction, rather than passenger presence alone, emerged as the predominant mechanism associated with distraction and elevated crash risk, although its effects varied across driver-passenger configurations and interaction contexts. The review highlights key methodological limitations such as inconsistent classification of passengers, lack of interaction effect modeling, underrepresentation of social distraction in crash databases, and limited evidence from low- and middle-income contexts. From a policy perspective, current passenger restriction measures, such as graduated driver licensing, remain overly simplistic, highlighting the need for more interaction-aware and context-sensitive approaches.