A person’s interaction with his environment comes largely from visual cues. Without this information, a pedestrian can trip over an unseen object or a driver might not detect a dangerous situation. In order to avoid these hazards, a person requires adequate lighting and should be provided with appropriate illumination for a given task. Low light or sudden changes in light, such as glare, can disrupt vision and lead to an accident. Often the question arises as to whether a person could have, or should have, seen a particular object or event. Often, this can only be determined through analysis and testing of the existing lighting conditions.