After one of them accidentally runs over his loving girlfriend, two teenage boys run away from home and travel the country looking for a safe place to dump the body. Short for time as the body rots, the two friends encounter plenty of bumps along the way, as their friendship and criminal minds are tested.

Guess I should have added that in! Well the night before (new years) the one who ran over his girlfriend had been drinking heavily and smoking weed, and the accident was caused because of the hangover/funk he was still in the next day and wasn't paying attention. Therefore he panicked and they ran away.

"After one of them accidentally runs over his loving girlfriend, two teenage boys run away from home..." -- This is confusing - do you mean that the girl is the girlfriend of BOY 1, and BOY 2 runs her over?

"...the two friends encounter plenty of bumps along the way, as their friendship and criminal minds are tested" -- Too vague and not very interesting. Be more specific.

Your logline begs several questions on the validity of your story's premise:

- If it's an accident, why not go to the police?
- Why is this accident the impetus for them running away from home?
- Why travel all over the country to dump a body? There's nothing closer? Why not just dig a grave in the woods? Doesn't make any sense.
- If your protag's goal is to dump his girlfriend's body before it rots, I'm not sure I want to spend any time with your protag.
- Your genre isn't clear. It feels like a mashup of thriller, road trip, coming of age. It just feels all over the place.
- Who is the antagonist?
- What are the stakes if they don't accomplish their goal? A really smelly trunk?
- How are they criminals? Are they juvies? You don't allude to this in the logline.

I like it. Personally, of what you wrote, this almost says it all, "Two teenage boys run away from home [and a psycho cop, or whatever the antagonist is] and travel the country looking for a safe place to dump the body."

You might want to add into the logline why they feel they have to hide the Body. From reading this logline it seems like running over the girlfriend was an accident, why not call an ambulance?