Morphine is a highly potent opiate analgesic drug and is the principal active agent in opium. Morphine is considered to be the prototypical opioid. Like other opioids (e.g. oxycodone, hydromorphone, and diacetylmorphine (heroin)), morphine acts directly on the central nervous system (CNS) to relieve pain. The effects created by morphine include euphoria and the feeling of well-being, relaxation, drowsiness, sedation, lethargy, disconnectedness, self-absorption, mental clouding, and delirium. When mixed with alcohol sedation, drowsiness, and decreased motor skills may occur. Id. According to NHTSA, in several driving under the influence case reports where the subjects tested positive for morphine, observations included slow driving, weaving, poor vehicle control, poor coordination, slow response to stimuli, delayed reactions, difficultly in following instructions, and falling asleep at the wheel. In the DUI context and field sobriety testing, horizontal gaze nystagmus, vertical gaze nystagmus, and lack of convergence are not present. Further, pupil size is constricted and there is little or no reaction to light. The subject's pulse rate, blood pressure, and body temperature are generally lower. Id.