Whiplash injury in low-speed traffic accidents are not objectively verified by medical equipment, thereby creating scope for misuse, which has resulted in huge social losses worldwide. The aim of this study was to examine the influence of low-speed vehicular rear-impact collisions on middle-aged men, and to analyze the head and neck injury criteria for the symptomatic human volunteers. Data was examined from the results of 50 dynamic sled tests, originally performed by Hong et al. (2012). In the previous tests, 50 men aged 30~50 years were exposed to an impulse equivalent to a bumper-to-bumper rear collision under medical supervision, and no resulting whiplash injury was identified. In this study, for 6 subjects who experienced dull aches over their bodies, head injury criteria (HIC₁₅) and neck injury criteria (N_km) were calculated according to the accelerations, forces, and moments at the occipital condyle measured by motion capture system. Although there were no changes in magnetic resonance imaging findings in all subjects at the pre-/post-test orthopedic examination, 6 subjects revealed mild aches around the shoulder, back, or lumbar area, and their symptoms disappeared within 2 days. The head and neck injury criteria, HIC₁₅ (3.086 ± 2.942) and N_km (0.077 ± 0.064) were obtained, and the maximum HIC₁₅ and N_km were found to be significantly lower than the critical injury assessment reference values (HIC₁₅:​ 700, N_km:​ 0.3). Moreover, even though 2 subjects were exposed to the same level of change of velocity (7.9 km/h), each N_km was significantly different (0.179, 0.057). One can therefore conclude that N_km can vary according to voluntary movements in the human subject.