The interior lighting in the 2013 Ford Fusion was designed specifically to consider the critical role lighting plays in relaying information to the driver.
Michael Arbaugh, chief designer for the Ford Fusion,  the first Ford vehicle to use only LED, or light emitting diodes exclusively througout the interior,  moves beyond simple functionality to helping scupt the environment inside the cabin. Lighting in a vehicle is about space and dimension, he says. With the right lighting, everything else falls into place,  he adds.
 Mahendra Dassanayake, Ford technical leader for Design, says, “Lighting gives you a sense of orientation. It’s a unique combination of functionality and comfort. Lights, graphics and displays are critical to drivers; we need to make sure that information is presented to the customer in an effective way,” he says.
Developing Ford’s signature ice blue color available in the ambient, or accent, lighting palette was critical, since it is a shade that can help keep drivers and passengers more alert. It makes it easier for a driver to absorb all the other messages coming from inside the vehicle, Dassanayake says.
The same balance has been used to make sure that the ambient colors available in the Ford Fusion enhance the driving experience,
  Ford researchers also have tested how the lighting affects the vehicle’s interior from the driver’s perspective, checking the textures and materials under a multitude of lighting conditions to make sure that glare and reflection are limited on smooth surfaces and that eye strain would be minimized.
 Colors also influence drivers moods.
 Certain levels or combinations of light trigger enzymes in the brain. Those enzymes cause emotional responses within the body - states we recognize as stress or calmness or happiness. “The emotions are created based on the secretions of these enzymes that are associated with certain light wavelengths,” Dassanayake said. “There are certain triggers.”
So it’s not your imagination - color can affect how you feel. In fact, it affects everything from your buying choices to your blood pressure. For example:
-- There are shades of yellow that stimulate parts of the brain, bringing clear-headed, decisive action
-- Green, on the other hand, affects the nervous system, causing us to breathe slowly and deeply, helping the heart to relax by slowing the production of stress hormones
-- Red - arguably the most attention-getting of colors - likely will evoke the strongest emotions, be that passion or anger
On the Ford Fusion, the palette is ice blue, purple, blue, orange, red, white and green. The palette allows the customer to set and change each color, depending on wants and needs.
With a seven-color palette, customers have several options. “We’re opening this up to let the customer decide,” Dassanayake said. “It’s offering them a choice,” Dassanayake says.
 “The brain does not see color,” he adds. “What we call color of light is actually a form of electromagnetic energy with different wavelengths.
“Light is like a pond, with ripples as the wavelengths. These ripples form and reflect and interact with each other, just like a ray hits a surface and sends a signal and then another sends a signal, and the sensation between the two is what people perceive as blue or red or green.” By Joseph Szczesny