Father, openour eyes on this prairie.Heaven, come downand brighten this highway.
Religious Imagery - The poem ends to sound like a prayer. "Father" can be used to connect the daughter's father to God as a father figure since her dad cannot always be with her. This shows trust in God as she moves into her future away from her father.
she zoomsluminous into a future onlyGod can see.
Imagery - the word "luminous" creates a hopeful imagery around the daughter's future, yet her future is unknown. Her father doesn't know where her life will take her, so he has to let go of her in some form. 
she drives cross-country
Symbolism - "Cross-country" driving can symbolize how the daughter is going into adulthood. She is physically moving away, but also moving into an adult life separate from her father. 
tumble into the roadbehind the car, fade into duskbehind the car
Imagery/Metaphor - Visual image being created of his messages being physically left behind the daughter as she makes her cross-country drive. This stands for the daughter moving toward her future while her father has to stay back and be okay with not following her everywhere she goes.
dad’s justcheckings and miss yous
Diction - The phrases used here sound like text messages and are super casual. They display how the father is still trying to stay connected to his daughter in a small way, but it is still emotionally impactful because of how much he misses his daughter.
Alone
Structure - This placement of the word "alone" by itself makes it stand out from the rest of the poem. It puts emphasis on the fact that the daughter is physically on her own, but it can also imply emotional distance from her father and how the father is feeling as she's becoming more independent.
while she’s learningto live on her own
Coming of Age - independence. The daughter in the poem is learning how to live a separate life from her parents (father), while the father is trying to learn how to give her space.
The hellos, jokes,missed calls here and there
Characterization - These small mentions of the father's action show how he is trying to stay connected to his daughter. These are generic things a normal parent may do, which makes the father/daughter relationship in this poem feel real.
he’s not allowed to caretoo much
Theme - This is the main conflict of the poem. The father being spoken about love his daughter immensely, but while she is becoming older and more independent, his love and care can feel overwhelming to her. The poem displays how a parent has to learn when to take a step back.