He reasoned that a buyer must assume that any used car is a lemon, because he has no way of knowing for sure whether that car has been abused or crashed. So a buyer, on average, is only willing to pay a below-average price. But the owner of a good used car knows that it is reliable, that he has driven it carefully, changed the oil regularly and maintained the car well.

If the owner of that good used car is not offered what he thinks it is worth, he won’t sell it, Dr. Akerlof reasoned. The overall quality of used cars goes down, because only below-average cars are offered, which drives down the value of used cars as a whole. The market is, in economics terms, broken, because the best cars in it are undervalued and are seldom offered for sale.

Because new car sales and leases dropped during the downturn, there are fewer of those to go around. So used-car prices have been rising over the last few years as recession-shy — and economics-savvy — drivers have pushed their cars ever farther.

With the value of some older cars actually rising, many drivers decided to drive their current car until it wore out. And because of the improving overall quality of today’s automobiles, many are discovering that it is entirely possible for a driver to wear out long before his or her automobile.

J. D. Power customer surveys of problems with new and three-year-old cars have shown, over the years, that cars are simply getting better. And that many of the problems that do surface involve new electronic gadgets like navigation, audio and phone systems that new owners may have a hard time understanding.

The trend toward better, longer-lasting cars seems to have begun way back in the ’60s, when the first imports from Asia started to encroach on American and European carmakers’ sales figures.