The backseat was scary. He was used to driving, or at least riding shotgun.
He wasn’t scared they would lose control, or even that they’d leave him at a gas station one day when he went in for a soda. (At least that would force his hand.)
No, what scared him was that when they made it, he’d feel even worse about himself. That he’d look back on the entire trip as a waste of time.
The car was going places though, so perhaps he could find a way to feel useful and enjoy the ride.