This paper focuses on how the behavior of drivers in response to warning systems is influenced by their trust in those warning systems. Our experimental examinations show that a) false alarms result in a reduction in trust and an increased reaction time to braking, b) a lack of alarms results in a delay in the recognition of hazardous situations, c) excessive trust induces significant delays in such situations and d) a lack of alarms more significantly reduces trust than false alarms do.