Japanese domestic market
This article needs additional citations for verification. (January 2017)
There is a common misconception that any Japanese branded car is JDM; however, this is not true. Only a vehicle made in Japan specifically to be sold in Japan is considered JDM.
JDM market cars when compared to the United States market where vehicle owners are now owning vehicles for a longer period of time, with the average age of the American vehicle fleet at 10.8 years, Japanese owners contend with a strict motor vehicle inspection and gray markets. According to the Fédération Internationale de l'Automobile, a car in Japan travels a yearly average of over only 9,300 kilometers (5,800 miles), less than half the U.S. average of 19,200 kilometers (12,000 miles).
Japanese domestic market vehicles may differ greatly from the cars that Japanese manufacturers build for export and vehicles derived from the same platforms built in other countries. The Japanese car owner looks more toward innovation than long-term ownership which forces Japanese carmakers to refine new technologies and designs first in domestic vehicles. For instance, the 2003 Honda Inspire featured the first application of Honda's Variable Cylinder Management. However, the 2003 Honda Accord V6, which was the same basic vehicle, primarily intended for the North American market, did not feature VCM, which had a poor reputation after Cadillac's attempt in the 1980s with the V8-6-4 engine. VCM was successfully introduced to the Accord V6 in its redesign for 2008.
In 1988, JDM cars were limited by voluntary self-restraints among manufacturers to 280 horsepower (PS) (276 hp) and a top speed of 180 km/h (111.8 mph), limits imposed by the Japan Automobile Manufacturers Association (JAMA) for safety. The horsepower limit was lifted in 2004 but the speed limit of 180 km/h (111.8 mph) remains.
Motorcycle power and speed restrictions
For many years Japan had severe restrictions on the maximum power and speed that motorcycles could have.
All motorcycles for the Japanese domestic market were restricted to 112 mph (180 km/h).
Power restrictions were as follows 
- 250cc class: 45 hp
- 400cc class: 60 hp
- 750cc class: 77 hp
- over 750cc: not allowed
- 250cc class: 40 hp
- 400cc class: 53 hp
- 750cc class: 77 hp
- over 750cc: allowed, but restricted to 100 hp
Japanese carmakers do not use a vehicle identification number as is common overseas. Instead, they use either a Frame Number, Chassis Number, or Vehicle ID Number and also a Model Code as well as an Emissions Code to identify their vehicles. The Frame Number identifies the vehicles model and serial number. For example, Frame Number SV30-0169266 breaks down as "SV30" identifying the model as Toyota Camry/Vista and "0169266" being the serial number of the vehicle. The Model Code designates the vehicle's model number and features. As an example, ST205-BLMVZ breaks down as "ST205", which means it is a third generation Toyota Celica GT-FOUR, and "BLMVZ" which designates a set of features incorporated in the vehicle. The Emissions Code refers to the vehicle's designated emission standard at the time, usually being placed before the vehicle's model number, and with the five most commonly used designations being E, GF, GH, ABA, and CBA. These codes are only seen on JDM models and are not present on exported models of the same type. Examples would include E-EK9 or GF-EK9 from the first generation Civic Type R, E-BNR32 from the R32 Skyline GT-R, E-JZX100 from the eight generation Mark II. Another useful example to help differentiate between pure JDM models and export examples is the code JHMEEG6 on the European Civic VTi models and E-EG6 on the Japanese fifth generation Civic SiR trims. Correct identification of the chassis code using these markers would help prove the authenticity of the model.
In the '90s the JDM power restrictions along with license restrictions that made it difficult to be licensed on larger motorcycles resulted in a number of models that were not offered anywhere else in the world, with 250cc and 400cc miniature replicas of the bigger 750cc & 900cc bikes.
At the same time, Japan had particularly tough laws regarding road licensing and sales regulations. Any motorcycle more powerful than 250cc had to take an extensively stringent test every two years.
Combining these factors with a virtually non-existent second-hand market made it economic to export the nearly new bikes abroad where they were eagerly bought and a number of import specialists sprung up to cater for this "grey import" market of relatively inexpensive but interesting motorcycles.
In the later '90s as Japan's economy fell into recession it became less profitable to export and Japanese owners held on to their bikes for longer. The last global crash all but ended the "grey import" industry with the big specialist importers closing down.
Cars manufactured for the Japanese domestic market have been growing in popularity since the late 1990s. Many car enthusiasts are attracted to JDM cars in different continents such as North America, Europe, Asia and Africa. Popular brands include Honda, Subaru, Toyota, Mazda, Suzuki, Lexus, Mitsubishi Motors and Nissan.
Ex-Japan Imports are also very common in New Zealand where 59% of vehicles registered on New Zealand roads originated from overseas markets as opposed to 41% of which were delivered NZ-New. Of this, 94% originate from Japan. New Zealand imported an average of 134,834 JDM vehicles per year in the period 2015–2019, the majority of which were Mazda 3 (Axela), Suzuki Swift, Nissan Tiida, Toyota Corolla and Mazda 2 (Demio). Other models popular for importation in previous years include exotic vehicles (Honda Tourneo, Nissan Skyline, Nissan Laurel and Toyota Altezza), and kei cars (Suzuki Carry, Daihatsu Move, Subaru R2). Due to the popularity of used imports from Japan, and their relatively poor crash-test ratings, the New Zealand Ministry of Transport is currently investigating tougher restrictions on imported vehicles, most notably on the importation of the Toyota Corolla, Mazda 2 (Demio) and Suzuki Swift.
In 2004, importing JDM cars became popular in Canada as highly sought after vehicles, such as the 1989 Nissan Skyline GT-R, became eligible to import under Canada's 15-year rule. In contrast, importing grey market vehicles into the United States is much more difficult. To avoid regulatory problems, most private individuals wait until EPA restrictions no longer apply to the desired vehicle, which is done on a rolling 25-year cycle.
Like in the Philippines, direct importers near ports in Subic, Zambales & Cagayan Valley have started their auction business to import quality vehicles preferably from Japan. And then so, most of the clients who are mostly operating bus companies based in Manila, Philippines began their interest to grow their transport business thru buying Japan surplus buses from all cities in Japan which are definitely cheaper than buying brand-new ones which are mostly imported from other countries and some are locally assembled coach bodies but still at an expensive price.
Used buses like in the Philippines also requires to convert from RHD to LHD conversion which is in compliance with the Philippine traffic law called Republic Act No. 8506 entitled "An act banning the registration and operation of vehicles with right-hand steering wheel in any private or public street, road or highway, providing penalties therefor and for other purposes." A violation of this law is punished by imprisonment for a period from two years, four months, and one day, up to four years and two months, plus a fine of 50,000 pesos (approx. $1,000). And most of the used buses from Japan in Manila, Philippines are mostly operating within the city and intercity travel which are at least 10 years of age after being phased out in Japan.
As early also in the 1990s, there is no exception that there will be a Japanese domestic market trucks to be called as "Japan Surplus Trucks" for auction & export to any of the developing cities in Asia and even including Russia. Most of the Japanese domestic market trucks that have been exported are Isuzu, Mitsubishi Fuso, Hino and some are Nissan Diesel. These trucks are also proven much reliable and durable since domestic trucks in Japan has no exception for the 10 to 15 year phased out due to the compliance of Japan's existing traffic & environmental regulations and also to avoid any taxes once any domestic truck unit surpassed the age limit to be phasing out.
Japanese domestic market trucks, or 'surplus trucks' after being phased-out in Japan, are extremely popular in the Philippines such as Isuzu Elf, Isuzu Forward, Isuzu Giga, Mitsubishi Canter, Mitsubishi Fuso Super Great & Hino Profia since they are popularly cheaper than buying a brand-new Japanese trucks which are locally distributed and even brand-new trucks from China which is about thrice as expensive as an ordinary used Japanese domestic truck units. Auctioneers in the Philippines also started importing trucks in the 1990s and it had been a staple for every small to medium business enterprise owner particularly in the logistics industry to support and to grow their respective businesses as well aside from being cheap than buying new ones, but also really proven that they are built to last.
Another category for Japanese trucks are the smallest ones, or to be called as kei truck, they are also extremely popular in the Philippines once again to be called as "multicab" which are often reconditioned & converted to any public transportation vehicle like jeepney since they are lighter, more economical, more environmentally friendly than the conventional Philippine jeepneys which are mostly powered by used diesel engines from Japan.
JDM specification model of vehicles oftentimes includes speed chime, that would ring if user has exceeded 105 km/h for standard cars, and 85 km/h for kei cars. This speed chime first mandated around on November 21, 1974, according to Article 1 of the "Ministerial Ordinance for Partial Revision of Safety Standards for Road Transport Vehicles", but soon abolished around 1986 with "Ministerial Ordinance for Partial Revision of Safety Standards for Road Transport Vehicles" (Ministry of Transport Ordinance No. 3 of 1986) due to non-tariff barrier pressured by US, and danger of drowsiness. Some model uses electromechanical system just like glockenspiel, but other model uses buzzer. Due to that, nickname for speed chime is kinkon.
Speed indicator light
JDM specification model of trucks (over 5 ton loading capacity, 8 ton gross vehicle weight) was mandated to have speed indicator installed from August 1967, according to Article 48 of the Ministerial Ordinance "Safety Standards for Road Vehicles" based on the provisions of Chapter 3 of the Road Vehicle Law.
The speed indicator light is only mandated for large trucks and is not necessary for small and medium-sized trucks and large buses, but installation on these vehicles are not prohibited. Speed indicator is installed in front of the cab, or up in the roof.
Article 48 of the Ministerial Ordinance "Safety Standards for Road Vehicles" based on the provisions of Chapter 3 of the Road Vehicle Law for speed indicator light is as following (modified and also translated):
- The speed indicator device shall be of a structure that automatically turns on the following number of lights (thereinafter referred to as "speed indicator lights") when traveling at the speeds listed in the table below.
- 40 km/h or less (*): 1 light
- Over 40 km/h up to 60km/h: 2 lights
- Over 60 km/h: 3 lights
- The speed indicator lamp shall not be equipped with a manual switch or the like that can easily turn off the speed indicator lamp, except for the power switch of the vehicle.
- The number of speed indicator lights that are on must be visible from a distance of 100m ahead.
- The light color of the speed indicator lamp shall be yellow-green.
- The display of the speed indicator lamp must be free of significant error when driving on flat paved roads.
- The speed display device shall be equipped with a light or other device that enables the driver to confirm its operating state from the driver's seat (usually they are located on speedometer).
Patterns for speed indicator is as following:
|Speed||Amount of light(s) turned on||Pattern|
|60 km/h and beyond||3||ON ON ON|
|40 km/h to 60 km/h||2||ON OFF ON|
|Below 40 km/h||1||OFF OFF ON|
|Vehicle stopped||none||OFF OFF OFF|
Abolishment and decline
Since it was enacted in 1967, this obligatory speed indicator light become non-tariff barriers, especially for European and American manufacturers. Because this law applies only to Japan, when importing heavy-duty trucks made outside Japan, it has to be modified in order to install the speed indicator light so the truck would pass certifications. Also, this was a system that was introduced to visually and intuitively (albeit roughly) easily distinguish the speed of the vehicle, but many people didn't even know what those speed indicator lights meant for.
This section possibly contains original research. (December 2021)
Some car enthusiasts like to build replicas of JDM vehicles from locally available cars. For example, enthusiasts in the USA will often take a US-market Honda Civic (sixth generation), convert it from left-hand-drive to right-hand-drive and source the required parts such as the engine and gearbox from the JDM EK9 Type R - which is based on the same platform - in order to make an 'exact' copy. Other forms of "JDM Conversions" include converting a USDM model first generation Subaru Impreza and fitting JDM STi parts to make it seem as if it is a genuine WRX STi model. In Southeast Asia, it is common practice to convert a base model Mitsubishi Lancer and swap out the necessary parts, right down to the cutting of the floor pan, and create a Lancer Evolution copy.
However, cars such as this would not be authentic JDM cars as they would possess a United States vehicle identification number. It is also to be noted that, even with such modifications, it is impossible to recreate the running performance of the original car, as there are many engineering aspects which cannot be replicated by means of "conversion" alone. A good example would be body strengthening methods using spot welding and extra reinforcement on strut mounting points, stress areas in joints, etc. as found in the Lancer Evolution and EK9 Type R models. These reinforcements are not present on base model sixth generation hatchbacks and Mitsubishi Lancers. Hence, replicas or conversions would be similar from a visual standpoint only, as they lack the same level of structural rigidity as the original counterpart.
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