Distracted driving may lead drivers to take wrong actions, possibly resulting in serious traffic accidents. The objective of this study was to apply a driving simulator to examine variations in driving behavior in presence of different secondary tasks. The driving behavior of 17 volunteers was determined by registering speed variations at selected positions of a curve in a virtualized highway. A comparison of driving performance between drivers fully aware of the driving activity and when they were engaged in a PASAT mental workload test was performed. Replicated analyses showed that distracted drivers did not recognize the beginning of the curve at the same level as they did while fully engaged in the driving task. They also drove through the curve at higher speed when distracted by the mental test. Driving performance was noticeably enhanced when drivers were aware of driving, thereby reaching high speeds in tangents, but noticing curves in advance to lessen acceleration. This study confirms that driving simulators are valuable for obtaining drivers’ behavior exposed to activities that could be very risky if in real situations.