Highway Blue by Ailsa McFarlane

Anne Marie's husband Cal left her on their first anniversary. Two years later and she is still adrift, living a precarious life of shift work and shared apartments.

When he shows up on the doorstep, clearly in trouble, she reluctantly agrees to a drink. But later that night a gun goes off in an alley near the shore and the young couple flee together, crammed into a beat-up car with their broken past, desperate to fill their lives on this long stretch of road under hot skies.

(Penguin)