My gut feeling is that part of this is because the average age of vehicles is increasing, and has been for a decade. People now own their cars for nearly twice as long as they did 15 years ago. Surely that entails many more maintenance costs.
But there’s probably something to the idea that deteriorating roads lead to automobile maintenance costs… Here’s the punchline from the WSJ article:
Using an infrastructure-specific inflation measure, the CBO estimates that in real terms highway spending by federal, state and local governments —which totaled $165 billion in 2014—has fallen by 19% from its peak in 2002. The American Association of State Highway and Transportation Officials says it would cost $740 billion to meet current demand.
Much of the cost is being transferred to individuals and businesses in the form of added vehicle repairs. “The consequence is that we’re all paying more to maintain our cars,” said Genevieve Giuliano, a transportation policy expert at the University of Southern California.
(On the other hand, the story also quotes the American Society of Civil Engineers, a group that might tend to overestimate the social benefits of road investments.)