How Automotive Quality Control Works

Image Gallery: Hybrid Cars Ford Escape SUVs roll off the line at Ford's Kansas City Assembly Plant in Claycomo, Mo. See more pictures of hybrid cars.
AP Photo/Charlie Riedel

Most people probably don't think too much about their cars on a daily basis -- unless he or she happens to be a real car enthusiast, of course. But for the vast majority of buyers, a car is simply an appliance. And, like the toaster or blender sitting on your kitchen counter, cars don't tend to take up a lot of space in their owners' brains. That is, until the car somehow breaks.

The thing is, despite recent high-profile recalls, on the whole, cars are more reliable than ever before. That's because car makers have begun to master a key step in automobile manufacturing: quality control. In any industry, quality control is a process that's used to insure that a product is free from bugs, operational issues and any number of other problems you can think of. In auto manufacturing, that means cars go through rigorous testing to make sure they're well-engineered, safe and comfortable.

The quality control process starts long before the first production models of a vehicle roll off the assembly line. When a car company releases a new product, they build prototypes, which are then tested to find weaknesses, mechanical problems and other details that could be improved. Once the prototypes have been vetted and polished, the design goes into production, where quality control continues on the production line, too. After being built, each car is tested for problems like fluid and air leaks, mechanical problems and proper assembly.

Keep reading to find out just how automotive quality control works and about the extreme tests that your car had to go through before it was allowed to hit the road.

Automotive Quality Control Techniques

Quality control is something that's a key part of almost every industry and every job. You probably engage in your own form of quality control several times a day. If you proofread your e-mail before you send it, that's a form of quality control. Even this article is the result of a type of quality control system. The editor who publishes it onto the Web site will check the published version for things like spacing issues, image size and position and broken links.

It's a similar process in auto manufacturing. But you can't put something through quality control until it's actually built. So, in automobile manufacturing, quality control starts with the prototype of a car. From there, the prototype is put through its paces.

Engineers have designed several tests to determine how well a car will stand up to real-world (and extreme) use. For instance, they drive the prototype car over specially designed surfaces to test the smoothness of the ride and the durability of the suspension. They also expose the cars to extreme heat and cold weather to test how the various mechanical components will work in all types of weather. They even fill a car with smoke and then check all the window and door seals to insure it's airtight.

One of the most well-known quality-control tests is the crash test. While most people are familiar with government and insurance industry crash tests, car makers also run their own tests to make sure its products and safety systems will work as they were designed to and protect the vehicle's occupants.

Up next, learn about some of the advances made in automotive quality control.

Advances in Automotive Quality Control

Russian workers assemble cars at the Volkswagen AG assembly plant in Kaluga, Moscow.
Russian workers assemble cars at the Volkswagen AG assembly plant in Kaluga, Moscow.
AP Photo/Alexander Zemlianichenko

So the quality control step of auto manufacturing seems pretty straightforward, right? You design a car, build a prototype, test the prototype and once you've worked out the kinks, start building production models. But, technological advances have made the crucial step of automotive quality control even more involved.

Now, quality controls tests can be more closely controlled, and even more extreme. While car makers still do a lot of testing in the real world (like driving through Death Valley, Calif., to test how well a car handles hot weather), they can mimic and even exceed real-world conditions in their own testing centers. Also, thanks to more precise sensors and computer programs, they can take more detailed measurements of a car's responses to the tests. Finally, they've also been able to add automated quality control systems to assembly lines, so something like a poorly fitted part or a bad weld can be automatically detected and dealt with.

Still, despite the incredible advances in automotive quality control, the most important component in building a quality car is the human touch. As a result, many car makers try to build a corporate culture where every single employee is responsible for quality. If they see a problem with a product, employees are encouraged to come forward so the company can make it right. Of course, that doesn't necessarily prevent all quality issues at the factory, but a sharp set of human eyes and a commitment to building the best car possible helps keep a company's cars safe and running properly.

For more information about automotive quality control and other related topics, test the links on the next page.

Related HowStuffWorks Articles


  • Comstock, Tom. "What Automotive Needs Right Now: Quality Control, Manufacturing Efficiency." IndustryWeek. April 7, 2010. (May 4, 2010) quality_control_manufacturing_efficiency_21493.aspx
  • Kleis, Mark. "Chevy's Department 180 returns -- this time with the Smoke Test." Left Lane News. March 29, 2010. (May 4, 2010)
  • Kleis, Mark. "Chevy's elite Department 180 demonstrates passenger rear end testing." Left Lane News. March 26, 2010. (May 4, 2010)
  • Kong, Benson. "Toyota Adds New Executive VP to Assist with Quality Control." Automobile Magazine. April 22, 2010. (May 4, 2010)
  • Schaffels, Brandy. "Chevrolet Engineers Show that Quality Control Can Be Fun." Feb. 3, 2010. (May 4, 2010)
  • Subaru of Indiana. "Manufacturing and Assembly." Summer 2004. (May 4, 2010)