Why Are Japanese Cars Limited To 112MPH/180KMH?

If you’ve ever driven a Japanese car made for sale originally in Japan (i.e. a JDM car – learn more here about the meaning of JDM) then you will have noticed that the speedometer reads a maximum of 180kph – 112mph.

This might seem a bit strange, as chances are the car you are driving is capable of exceeding that speed limit.

For example, here is a Japanese market speedo from a MK4 Toyota Supra – a “JDM” one:

And here is the same speedometer from a US market Supra:

 

You can clearly see the difference. The US market car reads up to 300kph (look at the inner yellow lettering) whereas the Japanese Supra only 180kph.

What’s more, it’s not just the readout of the speedometer that is limited to 112mph/180kph. The actual car itself cannot travel faster than the displayed limit.

If you try to exceed that speed in a Japanese vehicle, you will bump up against a hard speed limiter (often a fuel cutoff). You cannot go faster than that speed limit without modifying the vehicle.

But why are Japanese cars limited to 112mph?

What conceivable reason could the Japanese auto industry have for this madness? Especially considering that so many cars made in Japan are capable of hitting far more than this speed without breaking a sweat.

In this edition of Car Facts, we set out to examine the history and circumstances that have led to this particularly Japanese phenomenon.

One important thing to note is that this limit applies only to Japanese cars produced for the Japanese market. A 300ZX produced for sale new in the USA, for example, will not have this same limit. In New Zealand – where the editors of this site live – we have a large number of “Japanese import” vehicles (cars that were originally sold new in Japan and then have made their way to New Zealand). It’s not uncommon in our country to see cars with a 180kph speedometer and speed limit!

Street Gangs Prompt Action

From our research, one of the key reasons why Japanese cars are speed limited is to do with the rise of bosozuku gangs in the 1970s.

Bosozuku gang members (most commonly associated with heavily modified motorbikes, but also driving modified cars as well) would terrorise the highways and roads of Japan at high speeds according to this Japan Times article.

Gang members were notorious for exceeding posted speed limits, and adding a hard limit to Japanese market cars was seen as one way of trying to curb this undesirable and dangerous behaviour.

This introduction of more aggressive speed restrictions is also one of the reasons why Bosozuku started the trend of “stancing” cars and heavily modifying their appearance to make them as unique as possible.

An extreme example of a Bosozuku car

If you wanted to show off in your car in Japan, it was hard to do so at speed on the public roading system. Therefore, turning your car into an artwork was seen as a superior option. We hope to do more articles on Japanese car culture in the future as well, so stay tuned for more info.

A Desire To Avoid Road Deaths & Injuries

Another reason why Japanese cars have speedometer and hard speed limits is due to a desire to cut down road accidents, deaths, and injuries.

The Japanese Auto Manufacturers Association (JAMA) requested that members do more to discourage excessive speed on Japanese roads. In the 1980s, there were as many as 10,000 fatalities per year on the roads in Japan.

In a country where at the time the maximum speed limit was 100kph (60mph) and the fastest an average car could go around 180kmh, it was a limit that made sense.

This is also one of the reasons why – until 2004 – Japanese cars were limited (on paper) to 280hp; which we will cover in more depth in a future article. Everybody knew that cars like the R34 GTR produced more than the claimed horsepower limit, but there was a real desire to show restraint and sensibility on paper at least.

Conclusion – Why Are Japanese Cars Limited To 112mph?

To recap, Japanese cars manufactured for sale in Japan (this is the important bit, before we get a flurry of comments from people saying how their sold-new-in-USA Supra has a 180mph speedo) have historically been limited to 180 kilometres per hour – that’s 112 miles per hour in “freedom units” – due to a gentleman’s agreement between manufacturers to try to be seen to take action against excessive road injuries and fatalities caused by high speed crashes.

Bear in mind that this came against a backdrop of a nation that has fairly low speed limits and strict enforcement of speeding rules – it is only recently that the maximum speed limit on some sections of certain highways have been lifted to 120kmh.

Furthermore, in Japan there is a strong cultural concept of “mutual self restraint”, known as jishu-kisei. 

Whereas European and American manufacturers have always tendency to try and one-up each other with ever more powerful vehicles and dizzying performance figures, in Japan this approach has historically been avoided.

Japanese car manufacturers were not overly keen to get into an aggressive “arms race” with regards to how fast their cars could go; at least for the Japanese market itself. They were content to do this outside of Japan (presumably because they didn’t feel it would negatively affect their domestic reputation).

 

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