It all made sense
All of a sudden, it became clear why the car had been using so much money. The highway Davis was policing was close to the state’s border. The thief most likely wanted to cross over to the next state as soon as he possibly could because it would be much more challenging to apprehend him there.
Would he see the car again?
However, this also made Davis realize that he was unlikely to ever see this car again. What reason would the driver have to use this highway again if he was not a local? He began to feel as though his efforts had been in vain.