All the colours of the...
These are just my interpretations:
Red: Danger, Violence (Blood), Stop light, warning. But also Passion, Sexuality, Love. The Heart. Something deep within. Our life pulse. Desire, Wants.
Blue: Mystery ("Blue Rose" cases). Intuitiveness. Water.
Black: Darkness, death. Absence of light. Night.
Gold: Lauras orb was golden, the hit and run boy's soul was golden. The sun, light, life. The highest and purest "form". The most valuable essence.
Green: Green-lights: Move forward. The forest? Natural, connected to earth/nature.