Every month, all the major publicly traded car companies release sales reports broken down by brand and model. Sometimes, they’ll show the number of days that certain models stay on dealer lots. What they almost never mention -- at least, until provoked by trade publications such as Automotive News -- is the percentage of cars eaten up by fleet buyers.

It’s a somewhat dirty sales dance, the kind that’s one drink away from ruining the entire evening. Sell too few cars to fleets, and an automaker might miss out on big, regular orders from government agencies, police departments and megacompanies such as General Electric. Sell too many, and resale values can plummet because of the flood of used cars entering the market all at once. Go too hard on the discounts -- like when General Motors sold vehicles to Enterprise without standard side airbags, which Enterprise then sold to regular consumers as if they were fully equipped -- and an automaker can look like an unscrupulous cashmonger.

Speaking of General Motors, it's the reason we bring you this column today. On Wednesday, GM openly acknowledged that a 41 percent drop in rental sales was the main culprit for its overall 6 percent decline in U.S. sales in July compared with the same month last year. A similar drop happened at Ford, where 16 percent fewer fleet sales led to an overall 4 percent decline.

It swings the other way, too. In 2010, after billions in bankruptcy restructuring, GM and Chrysler quickly posted impressive sales increases that were largely due to fleet orders; at Chrysler, that was much as 39 percent of all U.S. sales at the time. In 2011, about a third of all Fords sold in the U.S. went to fleets. Even Toyota, a company that had always relied on its strong retail buyer base, flooded the rental market in January, to the point where just half of all Camrys sold that month went to regular folks like you and me.

Of course, we all need to rent cars now and again, and working vehicles that take heavy abuse have to be replaced sooner than pampered family rides. But it's tough to manage, especially for American brands that serve the commercial truck markets. At the end of the day, automakers have to balance fleet orders so they bring in enough profit without damaging the worth of their models. At worst, you get a car like the 2013 Chevrolet Impala, a bona fide fleet babe that’s already gotten so old she doesn’t even try to look decent in public.

So, since you’re presumably not looking to order several thousand pickups for your construction company, let’s have some fun with five classic American rental cars. Just because.

Chevrolet Corvette ZHZ

In 2008, Hertz purchased a few hundred Corvettes and dressed them up in the company’s yellow-and-black livery. Called the ZHZ, this Hertz-only coupe and convertible featured the 436-horsepower V8 engine and automatic transmission from the base car, but with upgraded brakes and the magnetic shocks from the pricey ZR1. At least two renters crashed them pretty hard, but you can be sure Hertz had made them sign their lives away well before that happened.

Shelby GT-H

What could be better than a yellow-and-black Corvette built solely for Hertz? If you’re a Ford fan, the Shelby GT-H from 2006 is the answer. Car and Driver rented four of them at once -- amid plenty of suspicion from Hertz employees -- and dumped the retro-styled Shelbys on a racetrack. The 500 that were produced were eventually sold to private buyers, not unlike the original Shelby GT350s Hertz rented back in 1966.

Chevrolet Impala

I’ve hated on the Impala before, and I’ll hate on it again. This is a lowly example of a full-size car that doesn’t even offer a navigation system, and if it weren’t for its direct-injection V6 engine and 6-speed automatic transmission, the Impala would be older than the Ford Crown Victoria, which is the only fleet car older than dirt itself. It's about to be replaced by the 2014 Impala, but it'll be a long time before the current models fade out.

Ford Crown Victoria

As a rental car customer, you’d have been insane to spend the money on a full-size/premium car to get this gas-guzzling Crown Vic with the wide front bench seats. This big, live-axle, rear-wheel-drive, 8-cylinder sedan was and is the police officer’s reason for being. It’s durable, cheap, loud and scary-looking, which is why it hardly changed for more than two decades. The final one rolled off the line in 2011.

Chrysler Sebring

The Chrysler 200 is apparently selling well, but since it's a halfhearted update of the old Sebring, we can’t let this one go. While designed to be an affordable, stylish sedan and convertible, the Sebring, like many of Chrysler’s products in the past decade, ended up languishing because of poor quality and downgraded equipment. Truth is, it was a fine car to rent while blasting the A/C in Florida. Outside the fleets, however, it was much worse. Two years ago, while on an assignment, I checked into a California motel in a Chrysler Sebring and wanted to kill myself from the shame (well, not entirely, but I did question why I was so broke). A sadder example: My former editor still drives a Sebring convertible and genuinely thinks he’s cool.

Clifford Atiyeh has spent his entire life driving and riding in cars he doesn't own. He was raised in Volvos and has grown to love fast, irresponsible vehicles of all kinds. He lives in Boston, is a member of the New England Motor Press Association, and has reported for The Boston Globe, Car and Driver, Popular Mechanics and The Times of London.