Up to 67% of accidents at Highway-Rail Grade Crossings (HRGCs) are due to motorists not stopping in time. To reduce the likelihood of vehicle-train accidents, the current study investigated the design of five novel visual and auditory in-vehicle notifications. An “Inform” notification was tested for “display time.” Notifications, “Slow,” “Intersection,” and “Stop” were tested for “display time” and “speech length”; a notification, “Over Tracks” was tested for “speech length” and “presentation order.” Twenty-six participants viewed driving simulator recordings, and rated the notifications at active rail crossing scenarios using Likert scales. The results showed that shorter speech length was preferred with delayed notification displays, and longer speech length was preferred with early notification displays. However, complex scenarios might require longer speech even with delayed displays, depending on additional variables such as driver speed or visibility. Additionally, the tradeoff between notifications being too urgent and startling should also be considered in safety-critical scenarios.