At one time, automobiles in the United States were big, boxy, and often covered in swathes of chrome. But over the years, vehicles have become more compact and streamlined, ditching chrome in favor of other options. The bulky bumpers that characterized American-market cars gradually disappeared as well, thanks to amended government regulations introduced in 1983.

Those regulations were set forth by the National Highway Traffic Safety Administration (NHTSA) and lowered the front and rear impact requirement from 5 mph to 2.5 mph. The updated rules also reduced corner impact requirements to 1.5 mph. These changes allowed automakers to be more flexible with their bumper designs. So, instead of relying on massive front and rear structures, designers could focus more on creating bumpers that blended into the vehicle’s body. As a result, the big and heavy bumpers that were the norm during the 1970s gave way to newer setups that were more integrated into the automobile’s overall shape while still offering protection in low-speed collisions.

This change came after the NHTSA reviewed both the costs and benefits of the Bumper Standard as it existed at the time. In a 1981 evaluation, the agency determined that the requirements, while strict, may not have benefited consumers enough. Taking the findings and public comments into account, the NHTSA amended the Bumper Standard in 1982, with the changes taking effect for 1983 model year vehicles.

During the early days of automobiles, carmakers used bumpers as protective equipment for the vehicle and its passengers. But bumpers were also seen as an important style element that added to the vehicle’s overall appearance. However, that changed when the NHTSA’s Federal Motor Vehicle Safety Standard No. 215 (FMVSS 215), known as Exterior Protection, was introduced for model year 1973. That standard listed a specific front and rear impact requirement, also known as the 5-mph bumper rule, leading automakers to design new, bigger bumpers to comply.

Some car manufacturers actually just attached large steel bumpers to existing designs instead, which contributed to the new era of bulky front ends. These new bumpers often extended farther from the body than previous structures, which increased the front and rear overhangs. They also added significant weight. Not all automakers went down this path, though; some chose instead to develop bumpers that fit the vehicle and didn’t ruin the lines. The Corvette C3 is a great example of this.

Today’s bumper systems are not as visible as they were in years past, with automakers now hiding the necessary safety components behind a plastic cover. Underneath that cover lies thick, energy-absorbing foam and metal reinforcement, a combination that allows manufacturers to maintain low-speed impact protection, per government standards, without compromising on aesthetics.