The average car-loan payment has hit a decade high.

It's a result of Americans' renewed zeal for trucks and SUVs.

But the keenness for big cars — and the ease with which lenders have issued car loans to even high-risk recipients — has boosted loan delinquencies to record highs.

The average car-loan payment just hit a decade high, according to Experian data first reported by Automotive News.

In the fourth quarter of 2018, the average car loan in the US was $545 a month for new cars and $387 a month for used vehicles. The average interest rate was 6.3%, also a decade high, according to the auto watcher Edmunds.

One driver of that is the ever-increasing American interest in SUVs, trucks, and crossovers, Edmunds' manager of industry analysis, Jeremy Acevedo, said.

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"Right now, one of the driving factors behind that is that Americans (are making) a massive shift to SUVs and trucks," Acevedo told Business Insider. "It's driven the prices up to unprecedented levels, so much so that today's average vehicle price is up to $36,000."

Americans have been buying more and more big cars. In the early 2010s, as Bloomberg reported, sales of trucks and SUVs started to overtake those of small and medium-size cars. Experts now forecast that by 2022 under 35% of new-car sales will be passenger vehicles and more than 65% will be trucks and SUVs.

LMC Automotive estimated that by 2022 84% of General Motors vehicles sold in the US would be a truck or SUV, CNBC reported. For Fiat Chrysler, that ratio will be 97% and 90% for Ford.

The dark side of America's big-car obsession

Middle-class Americans can't easily afford trendy big cars. Take the Ford F-Series — it's America's top-selling car, but its starting price of $28,000 doesn't render it as affordable as, say, a $14,000 Ford Fiesta. A survey released by the US Federal Reserve in 2017 found that the average American household had less than $9,000 in savings, with nearly a quarter unable to cover their living expenses from their emergency savings accounts.

As a result, Acevedo said automakers had increased lease terms to stretch the length over which car payments are made. "We've seen automakers do really whatever they can to make this a pill that shoppers can swallow," Acevedo said of the cost of big cars.

And, keen on selling these big vehicles regardless, lenders have been offering loans to just about anyone — even those with credit scores under 600. As Business Insider's Frank Chaparro reported in 2017:

"According to data from Experian, the balance of deep subprime loans — those given to people with credit scores of 300 to 500 — increased 14.6% from 2015 to 2016.

"Subprime loans — those given to people with credit scores in the range of 501 to 600 — increased by 8.6%. This is far higher than the growth of prime loans, which witnessed 6.2% growth."

But that zeal to give car loans to nonideal candidates is starting to show its downsides. Last month, the Federal Reserve Bank of New York reported that more than 7 million Americans were at least 90 days behind on their auto loan payments — a record number. And, according to Morgan Stanley, the 30-day delinquency rate for Capital One's auto-finance operations have posted year-over-year increases through January 2019 for 18 consecutive months.

Read more: A record 7 million Americans have stopped paying their car loans, and even economists are surprised

For that reason, Morgan Stanley's auto analyst team told investors in a March 8 note to "Tread carefully" when it came to auto stocks.

"The auto credit party may not be over yet, but the lights are starting to flicker," they wrote.

"In that post-recession auto market, access to credit is really the biggest facilitating factor," Acevedo said. "It's been extended a little farther down the market than we've seen in the past, but really it’s just a story of sheer volume, of people getting sustained low rates for a long time and in doing so they bought expensive vehicles."