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Rear-end crashes account for more than one in five fatal crashes in the U.S. The rear-end crash scenario most commonly associated with fatal crashes involves a following vehicle traveling 40 to 70 mph closing on a lead vehicle at a rate greater than 30 mph. The current research compiled an analysis of the literature to identify the kinematic factors, environmental factors, traffic-related factors and individual differences that are likely to influence drivers’ responses when closing on a slower-moving or stopped lead vehicle [LV]. In Part 1, several primarily kinematic-based methods for modeling drivers’ responses to a LV were compared for high-speed closing events. Methods utilizing looming (angular growth rate) equations were shown to predict drivers’ responses and time-to-contact methods (Inverse Tau) were conditionally accurate when applied to specific crash scenarios. However, the ratio or nominal response time methods did not predict drivers’ responses in most crash scenarios.