Why Are Some Cars Limited To 155 MPH? (Explained & Solved)

You may have been wondering why some cars have a limited speed of 155 mph, and you probably might have guessed and come to a vague conclusion about why it is so.

Some car enthusiasts and speed daredevils find this very upsetting because it does not produce the adrenaline rush that they are accustomed to and crave.

Well, whatever the case, some reasons, and events led to some cars being speed limited to 155 mph. this article explores and explains why some cars are limited to 155 mph.

Here’s the Short Answer to Why Some Cars Are Limited to 155 Mph:

In the late 1970s, there was worry over Germany’s autobahn speed policy.

These eventually led the three leading car manufacturers in Germany to have an agreement to limit most of their standard edition cars to a maximum of 155 mph.

Do Car Manufacturers Limit Cars to 155 Mph?

Some car manufacturers limit some of their car models, especially the standard edition models, to 155mph, as you might have noticed.

Some car manufacturers limiting their car’s speed limit to a maximum of 155 mph is not something that occurred overnight.

Back in the late 20th century, the 70s in particular, there were concerns about the harmful and toxic environmental pollutants that were emitted into the atmosphere.

The European Union (EU) began research into the amount of unhealthy environmental contaminants, most notably the negative effects of carbon dioxide.

Within this same period, the automobile industry was in its early booming stage, which witnessed the increase in power and performance of different car brands.

Due to this development, the carbon dioxide (C02) rate in the atmosphere increased. Germany was pivotal and played a leading role in the industry.

This prompted the European Union (EU) to probe and examine the effects of cars and how they affect the environment in general.

Ever heard of the Autobahn? It’s a long stretch of road in Germany that has no limit whatsoever to how fast you can go.

On this stretch, one can step the hardest on the gas pedal and squeeze all the power of the car’s engine without worrying about speed tickets.

This is where you can test your car’s maximum performance without interruption.

The autobahn was another source of worry, as it was seen as a gateway for accidents and other hazardous road incidents.

The above circumstances led three major German automobile manufacturers to have an agreement known as “The Gentlemen’s Agreement”.

The said automobile manufacturers were Mercedes-Benz, BMW, and Audi. They agreed that they would respectively limit the speed of most of their standard edition cars to a maximum of 155 mph.

Meanwhile, BMW models have their 0-60 mph times. If you’re more interested in how quickly Volkswagen cars accelerate, explore Volkswagen 0-60 mph times instead.

It is worthy of note that the decision or agreement by these automobile heavyweights was done out of sheer will and not based on mandate or authority.

It was a gesture to show their support for the environmental cause and also for road safety concerns.

Why Aren’t All Cars Limited to 155 Mph?

Different regions or continents have in place different policies and standards of living set for the people, and the automobile sector is not an exemption.

Remember that the three auto manufacturers that agreed on the 155 mph maximum speed limit were all German car makers.

The 155 mph maximum speed limit was put in place primarily by German automakers, specifically for their respective car brands.

The Germans have no power to force other auto manufacturers elsewhere to tag along with their agreed speed limit of 155 mph.

Similarly, Japanese car manufacturers in the 1980s, amid concerns about injuries and deaths caused by car accidents, came together and had a consensual agreement.

They had a “Gentlemen’s agreement” to manufacture cars that would not exceed the 112 mph maximum speed limit for Japan’s domestic market (JDM).

However, things took a different turn of events in the 90s when cars were being upgraded with more powerful and high-performance engines.

Some Japanese auto manufacturers only heeded the agreement on paper, while in reality, they manufactured cars that had more than the agreed speed limit of 112 mph.

The automotive industry in general does not have a stipulated speed limit law or rule that controls the maximum speed limit for cars that are produced worldwide.

Hence, most car manufacturers are at liberty to make cars that best suit their tastes and needs.

In today’s world, where competition is the order of the day, most car makers are tirelessly working to produce powerful and high-performance cars built for power and speed.

Hence, how can they all be limited to a meager 155 mph?

How Can You Know if a Car Is Speed Limited?

To know if your car is speed limited, it is important to be aware that there are different types of speed limiters in cars today. Different car brands and models have disparate forms of limiting the cars’ maximum speed.

All cars are technically speed limited by their gearing. However, some cars have low gearing that is artificially oriented, while others rely on the use of electronic speed limiters to get the job done.

You would know if your car is speed limited by the artificially low gearing method if the car’s speedometer hand never goes beyond a particular number of mph no matter how hard you step on the gas.

This would simply mean that the car was speed limited to a particular agreed number by the manufacturer.

Another way to know that your car is speed limited is by simply looking at your car’s steering wheel and dashboard.

This is because some modern cars come standard with pre-installed speed limiters that can be activated to work and deactivated when it is not needed.

These speed limiters are controlled by a button on the steering wheel with the letters “LIM” or an indicator stalk. You should also know whether electric cars have lower top speeds.

How Exactly Does the Speed Limiter Work?

A speed limiter, also called a “governor,” operates through electronic sensors and an engine computer.

These electronic sensors have the job of detecting how fast the car is going and then sending this information to the engine’s computer.

The engine’s computer is responsible for overseeing most of the engine’s functions.

Once the car reaches a predetermined set speed limit, the engine’s computer automatically restricts the flow of fuel and air into the engine, and the sparks that cause combustion.

This way, the car is not able to go beyond the speed limit predetermined by the manufacturer.

Another type of speed limiter, also referred to as Intelligent Speed Assist (ISA) in modern cars, usually works in two ways. The first is the manual way, where one has to set the speed manually to the desired speed limit.

After the desired speed has been set, the car will not go faster than the set speed no matter how hard the driver steps on the acceleration pedal.

The Intelligent Speed Limiter (ISA) works quite differently from the manual system speed limiter. This speed limiter uses GPS and camera-based traffic-sign recognition technology in the car to know the speed limit of every road one is on.

This way, the speed limiter detects the maximum speed limit on a particular road and adjusts the car’s speed limit accordingly. You would want to know how Teslas respond to speed limits on autopilot.

Can You Disable the Speed Limiter?

Disabling the speed limiter in one’s car is possible, but it is not the easiest thing to do because some cars have in-built systems that are set to defeat any meddling or tampering of the governor.

However, like most computers, a car’s engine computer can also be modified and adjusted. This is possible through the use of an aftermarket performance chip, which can remove the maximum speed limiter and also adjust the rev limiter.

Disabling your car’s maximum speed limiter involves a software variation or modification in the engine management system of the car.

This alters the performance of the car’s engine and increases the power and fuel economy of the engine. It is done by specialists who are well acquainted with the speed limit in cars, also known as tuners.

Another method of disabling a car’s speed limit, especially in relatively older model cars, is by mechanically disconnecting the sensors in the transmission.

This way, the car’s engine computer is unable to know the engine’s Revolutions Per Minute (RPM), hence, a stalled speed limiter.


How Speed Limiters Work | HowStuffWorks


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