Strangely enough our eyes do not see things quite as they are; an example of this is artificial light. There are a fare amount of different types of artificial lights and each of these lights tend to let off different colors. Mercury vapor lets off green color, high-pressure sodium lets off an orangey yellow color, and tungsten light is very orange. These types of light are the most common and appear to be white to us, most of the time. Parking lots normally use sodium vapor bulbs because they use less energy; therefore the company that owns the lot can cut down on electric costs. The picture of the flowers is most likely sodium vapor light.
It is important to know these lights because they will affect the way your images come out. Especially if you don't have a flash and have to relay completely on the light around you to light your subject.