The Lexus Global website has an in-depth interview with Yasuo Kajino & Shinno Kato, two of the people responsible for the design of the 2013 ES — here’s an example of the level of detail & forethought:
We have introduced lighting linked to driving stages.
When [the ES is] stopped, the ambient lighting is bright. As the door is closed, the ambient lighting is completely off. Once the engine is running, the lights come back on again. Then, as vehicle starts moving, they dim. This is our way to cue anticipation of the act of driving.
Always enjoy getting insight into how vehicles are designed — definitely worth reading the entire interview.