The stereotype of a sleazy used car salesman pedaling lemons isn’t universally true, but it wasn’t created out of thin air either. The fact is, not all used automobiles are safe to drive. Last year, consumers purchased over 5 million cars that had been subject to a recall but were never repaired, according to the vehicle history service Carfax.

Rosemary Shahan, president of Consumers for Auto Reliability and Safety, recalls a “heartrending” case in which a teenager died in a head-on collision because the used pickup truck the he was riding in had been sold without adequate safety features.

“A rebuilder cut corners and instead of installing [replacement] air bags, he stuffed paper into the empty compartments where the air bags belonged,” says Shahan. “Bobby always wore his seat belt. But without the air bag, that was not enough.”

If you're going to buy a used vehicle, do some legwork and research first. “It's smart to take your time and shop for a car before you are under a lot of pressure to buy one right away,” says Shahan. “It's better to rent a car for a while and give yourself time to find the right car.”

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Get a history lesson

When shopping for a used vehicle, ask the seller about past damage and request copies of all maintenance and repair records. Ask to see the title and look for what's called a Title Brand — a descriptive label such as “junk,” “salvage” or “flood” — indicating that the vehicle suffered severe damage in the past, according to the National Motor Vehicle Title Information System.

Then conduct your own investigation on these free sites:

  • The National Insurance Crime Bureau, which allows you to check a vehicle's VIN (Vehicle Identification Number) for reports of severe damage and whether it was ever stolen

For just a few dollars, you also can purchase a Vehicle History Report that includes more extensive information, including the number of miles driven and ownership history.

Give it a check-up

Hire a mechanic from an automotive diagnostic service to give it a thorough inspection and hand you a written report on its condition. Choose your own mechanic, even if the seller claims to have already inspected the vehicle.

“Today's cars include highly sophisticated computerized systems,” says Shahan. “It takes a skilled, experienced technician with expensive diagnostic equipment to perform important diagnostics.”

If you’re savvy about auto repair and want to perform an inspection yourself, Consumer Reports suggests you look for these signs of prior damage:

  • Paint sprayed over the original paint job
  • Parts that don't fit together right
  • Mold or mildew smells
  • Bad wheel alignment
  • Uneven tire wear
  • Non-working lights
  • Signs of welding on the frame
  • Kinks or dents in the fuel tank or floor pan

Dealers are required to post a written Buyer's Guide on most used cars and light trucks. It will tell you whether or not the dealer offers a warranty and, if so, what it covers. If there is no warranty or if it doesn't cover all systems, ask your mechanic if the vehicle has problems.

When you take the vehicle for a test drive, the Federal Trade Commission suggests you try it out on hills, highways and heavy traffic. Feel whether the steering wheel shimmies on the freeway. To test the brakes, drive to a place where nobody is behind you (to prevent being rear-ended), then brake three or four times. If the vehicle pulls to the right or left, the brakes need work, according to the Ohio Bureau of Motor Vehicles.

Related: Road Trip Checklist for Your Car

Certified pre-owned or used?

Some used cars are advertised as “certified pre-owned,” or CPO, indicating they have been tested and repaired to a high safety standard. However, controversy exists over that designation because no central authority governs its use.

Some CPO cars really do get a thorough check. “Certified pre-owned vehicles from new car dealers undergo very thorough inspection procedures and background checks,” says Mike Calkins, manager of technical services at AAA. “Any car with significant prior collision repairs cannot be sold as certified pre-owned. Certified pre-owned vehicles come with an extended warranty backed by the vehicle manufacturer.”

If you want to buy a certified pre-owned car, the key is finding a reputable and responsible dealer. Since there is no governing agency, there's nothing to stop a shady sales lot from slapping a CPO label on vehicles that haven't faced a thorough inspection. 

“Some so-called 'certified' cars are 'chop-jobs,' halves of two different cars that were welded together. They're grossly unsafe and prone to literally splitting in two in a subsequent crash,” she says. ”Save your money. Buy a non-certified car, and get your own inspection done.”

Related: Why You Should Let Your Teen Drive the Newer Car

David Arv Bragi is a freelance journalist and marketing consultant. He has been writing about health and safety issues since the 1990s and currently lives in Portland, Oregon.