Being able to adequately see the road ahead to observe conflicting traffic and the behavior of other highway users, including where bicycles and pedestrians are present, is integral to driving. Illumination significantly improves the visibility of the roadway, increases sight distance, and makes roadside obstacles more noticeable and therefore more avoidable.

In addition to traffic safety, adequate lighting provides benefits in terms of personal security. Roadway illumination often serves the purpose of safeguarding personal safety for pedestrians, bicyclists, and transit users. Darkness can reduce personal security. Walking, bicycling, or commercial activities may become uncomfortable or unsafe if adequate illumination is not provided. Therefore, ensuring that the lighting provides acceptable levels of illumination can be a great benefit to all users of the roadway environment.