In general, many persons with color blindness experience few, if any, challenges. They are able to perform most everyday tasks, including driving. Color-blind people can generally identify the colors red, orange, yellow, green, blue, indigo, and violet. They may have difficulty distinguishing some colors, such as greens, or they may see only shadows of colors. There are several types of color vision defects that affect different people in different ways. The two most common types are deuteranopia and protanopia. People with deuteranopia cannot distinguish shades of red and often mistake brown for black and white for red. These individuals will require all vehicles to be either completely dark-colored or entirely light-colored in order to avoid accidents. People with protanopia cannot distinguish shades of green and often mistake purple for black and white for green. Although these individuals can see other colors just fine, they will also be at risk for having an accident if they are not given adequate warning by vehicles that are gray instead of white or black instead of dark gray. Color blindness is more common than you might think. As much as 9 out of 10 men are affected by some form of color blindness.