Even car companies have reason to worry about their report cards.

Consumer Reports released its annual Top Picks and Brand Report Cards today, and in a shock for traditional automakers, its Best Overall vehicle award went to the Tesla Model S electric car.

The magazine's Top Picks and Brand Report Cards are a set of ratings for vehicle quality that are scrutinized by new-car buyers just as thoroughly as stern parents pore over grade-school report cards.

The award for the Tesla may not be too surprising, given the magazine's ongoing love affair with the Model S.

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When it joined the Consumer Reports' fleet last year, the all-electric Model S luxury sedan became the highest-rated car tested since 2007, and it has continued to impress the staff.

2012, 2013, and 2014 Toyota Prius

2012, 2013, and 2014 Toyota Prius

Another non-surprise was the choice of the Toyota Prius hybrid as Best Green Car.

The Prius has held that title for 11 consecutive years, and in fact only one other car--the 2003 Honda Civic Hybrid--has ever received the award.

However, the addition of the Ram 1500 pickup truck to Consumer Reports' Top Picks list was surprising.

Named Best Pickup Truck, the Ram was the first Chrysler product to make the list in 16 years.

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For the 2014 model year, the Ram 1500 EcoDiesel will join the lineup with a 3.0-liter diesel V-6 and EPA fuel-economy rating of 23 mpg combined.

The magazine's praise for the Model S and Ram 1500 indicate that Japanese carmakers' grip on the Top Picks list is beginning to loosen--but the Brand Report Cards tell a different story.

2014 Ram 1500 EcoDiesel

2014 Ram 1500 EcoDiesel

Lexus got top marks for the second year in a row, followed by Acura and Audi.

In fact, seven of the top eight spots were held by Japanese brands.

Subaru, Toyota, Mazda, Honda, and Infiniti, finished right behind the top three, while Nissan was the only Japanese brand not in the top half of the rankings.

Reliability issues attributed to recent redesigns of the Altima and Pathfinder, and mediocre road-test performances by the Sentra and Versa brought Nissan down five spots, to 18th place out of 23.

Meanwhile, Jeep and Ford tied for the lowest score; fellow Detroit brands Dodge, Cadillac, and Chevrolet rounded out the bottom five.

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