(What is Hel's color?)

[laughs] This is one of those details I pulled out of thin air, but I love your theory about how it was chosen to draw Michael in. Cyan (or other brightly-coloured) cadillacs on desert roads are a classic mental image for me denoting long, open journeys and this whole story started with that.

I'm glad you enjoy the detail, even if I don't always have an explanation. ;P