If you’ve ever looked at your car’s speedometer, you may have noticed that it often goes well beyond the legal speed limits in the United States. Most highways cap out at 65–85 mph, yet even modest family sedans can reach speeds above 120 mph. Sports cars and high-performance vehicles can exceed 200 mph. This raises a common question: why are car manufacturers allowed to make vehicles capable of traveling over 100 mph when drivers are never legally permitted to do so?
Safety Standards vs. Legal Speed Limits
The first distinction is that speed capability and legal speed limits are not the same thing. Manufacturers are required to meet federal safety standards set by the National Highway Traffic Safety Administration (NHTSA), but these standards do not impose a maximum top speed requirement. Instead, they focus on crash safety, emissions, braking systems, and other regulatory factors.
Laws about how fast you can drive are determined at the state and local level. That means your car may be capable of traveling at speeds far beyond what is legally allowed, but you can still be ticketed—or arrested—for attempting it on public roads.
Engineering & Performance Expectations
Modern cars are built with powerful engines for reasons beyond speeding:
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Highway Merging & Passing Power: Cars need to accelerate quickly and safely to merge onto freeways or pass slower traffic.
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Durability & Efficiency: Engines designed with extra performance headroom often last longer and handle stress better at normal driving speeds.
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Global Market Standards: In countries like Germany, parts of the Autobahn have no speed limit. Automakers build vehicles for a worldwide market, not just U.S. laws.
Consumer Demand & Marketing
Automotive culture has long celebrated performance, horsepower, and speed. Even if drivers never push their vehicles past 80 mph, knowing a car could go 140 mph is part of the appeal. Automakers compete by advertising acceleration times (like 0–60 mph) and top-end power. This is especially true for sports cars, luxury vehicles, and performance trims.
Track & Private Use
Cars capable of more than 100 mph aren’t necessarily intended for the street. Many enthusiasts take their vehicles to:
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Race tracks
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Private courses
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Performance driving schools
In those environments, higher speeds are both legal and expected.
Legislative Attempts to Limit Car Speed
Although most vehicles today are capable of traveling far faster than any legal road limit, lawmakers have occasionally tried to rein in manufacturers. The debate resurfaces every decade, usually after spikes in road fatalities or technological changes.
U.S. Proposals
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1970s Oil Crisis & Safety Push: During the 1973–74 oil embargo, Congress considered requiring cars to include speed governors to conserve fuel and reduce crashes. Instead, the National Maximum Speed Law (1974) capped highway limits at 55 mph. Manufacturers weren’t forced to restrict cars, but they were pressured to design dashboards that made 55 mph visually prominent.
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1990s Electronic Governors: As more cars adopted electronic control units (ECUs), safety advocates proposed mandating top-speed limiters. These proposals never became law, but some manufacturers voluntarily capped vehicles at 112 mph (180 km/h) in the U.S. market.
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Recent Bills: In 2019 and 2021, federal lawmakers floated ideas tying federal highway funding to states that adopt stricter speed controls or mandate speed-limiting technology for repeat offenders. These bills stalled amid pushback from the auto industry and drivers’ rights groups.
Europe’s Stricter Approach
The European Union has moved faster than the U.S. on electronic enforcement:
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Since July 2024, all new cars sold in the EU must include Intelligent Speed Assistance (ISA) systems that detect local speed limits and warn drivers—or actively reduce throttle power—if they exceed them.
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Germany, home of the Autobahn, resisted strict speed caps but accepted ISA technology as a compromise between safety and consumer freedom.
Industry Self-Regulation
Some automakers, particularly in Europe, have taken matters into their own hands:
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Volvo announced in 2020 that it would limit all new cars to 112 mph (180 km/h), citing road safety goals.
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Other luxury brands, like BMW and Mercedes-Benz, have “gentlemen’s agreements” to electronically cap most models around 155 mph (250 km/h), even though the cars could go faster.
Why These Attempts Often Fail in the U.S.
Efforts to legislate vehicle speed caps in the United States face resistance because:
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Driver Freedom – Americans often view driving as a personal liberty.
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Geography – Long, wide highways in rural areas make higher speeds feel safer than in dense European cities.
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Enforcement Priority – Lawmakers prefer focusing on enforcement tools like cameras, fines, and license suspensions, rather than restricting manufacturers.
The Role of Technology in Speed Enforcement
Instead of limiting car capabilities, governments increasingly rely on:
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Speed cameras and red-light cameras to enforce laws.
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Intelligent Speed Assistance (ISA) technology, already mandated in Europe starting 2024, which warns or limits drivers when they exceed posted speed limits.
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Telematics and insurance monitoring that track driving behavior.
This shows the trend is moving toward monitoring drivers, not restricting manufacturers.
Conclusion
Car manufacturers are allowed to make vehicles that travel well over 100 mph because engineering, consumer demand, and global standards require it. While drivers are legally restricted by speed limits, automakers design cars with performance headroom for safety, durability, and worldwide use.
Although legislative attempts to restrict speeds have been made in both the U.S. and abroad, most have failed in America due to cultural resistance and practical challenges. Instead, enforcement technology and penalties for drivers remain the preferred tools.
So the next time you glance at your speedometer, remember: just because your car can go 120 mph doesn’t mean you should—or legally can—on public roads.