Naturalistic Driving Study (NDS) is a research area that is potential for collecting data on driver performance, i.e. behavior in normal, impaired and risky situations based on human factors. This work investigates results of a cognitive assessment tests targeting different human factors including visual field, reaction speed, driving behavior and personality traits of drivers in an NDS. Frequency of being involved in Near Miss event (fnm) and Frequency of committing Traffic Violation (fv) are defined as indexes of safe driving in this work. Inference of association shows statistically significant correlation between Standard Deviation of Reaction Time (σRT) and both safe driving indexes fnm and fv. Causal relationship analysis excludes age as confounding factor as variations in behavioral responses is observed in both younger and older drivers of this study.