Kei car

 ( 1949 Introductions ) 

Emissions laws were another problem for the kei car industry in the mid-1970s. From 1973 to 1978, emissions standards were to be tightened in four steps.

Most manufacturers were somewhat surprised by the decision; having expected a limit, they had already developed new engines to fit such restrictions. These new engines were quickly introduced, usually mounted within widened bodies of existing models. These interim versions, with displacements ranging between 443 and 490 cc, were "feelers", developed to see if a continued market existed for the kei car. As sales improved, these engines only lasted for a model year or so until manufacturers had the time to develop maximum-sized engines. Only Daihatsu had a 550 cc engine ready and thus avoided developing transitional engines that did not immediately take full advantage of the new regulations. Kei car sales remained stagnant, however; while combined passenger and commercial kei car sales reached 700,000 for the first time since 1974, the small cars still lost market share in a quickly growing market.

As the kei cars became larger and more powerful, another benefit appeared as exports increased considerably. In particular, export sales of kei trucks increased, while kei passenger car exports increased at a lower rate. In 1976, the number of exported kei cars and trucks combined was 74,633 (up 171% year-on-year), despite exports of passenger kei cars decreasing. In 1980, another record year occurred as exports grew by 80.3% (to 94,301 units), of which 77.6% were microtrucks. Nearly 17% of exports went to Europe, dwarfed by Chile, which took nearly a quarter of the exported kei vehicles.

Due to the difficult economic environment, low-priced cars sold well at the turn of the decade; 1981 marked another successful year as Japanese kei car sales reached their highest since 1970 (at 1,229,809 units for cars and trucks). This was also thanks to a new phenomenon: To help boost their sales, Suzuki developed a new car which could be sold as a commercial vehicle although it was really intended for private use, thus avoiding the 15.5% excise tax. Efficient, bare bones design meant that the resulting Suzuki Alto was considerably cheaper than any of its competitors, and it set the tone for kei cars for the entire 1980s. Until the excise tax was abolished in 1989, light commercials like the Alto and its competitors nearly completely supplanted the passenger car versions.

As the 1980s progressed, kei cars became increasingly refined, losing their utilitarian origins, as Japanese customers became ever better off. Features such as , turbochargers, four-wheel drive, and air conditioning became available on kei-car models. Conversely, van versions of kei hatchbacks were now marketed to non-business customers to take advantage of even lower taxation and more lenient emissions rules; this move in the market was spearheaded by Suzuki with their 1979 Suzuki Alto, and competitors soon followed suit, with the Subaru Family Rex and the Daihatsu Mira appearing within a year's time.

In the 1980s, the speed limit for kei cars was . Government rules also mandated a warning chime to alert the driver if this speed was exceeded.

For the first time, a Horsepower limit of was also applied in addition to the limit on engine size, in response to the ever-increasing power outputs available with turbocharging and multivalve technologies popularized in the late 1980s. Engine technology was also shared with sport bike, which are designed more for rider enjoyment and less so for fuel economy, going against the idea of small people's cars and putting the kei cars' tax and structural advantages at risk of a governmental backlash. This power limit matched the highest output reached by any kei manufacturer at the time and was a gentlemen's agreement amongst the manufacturers in an effort to avoid a kei-class horsepower war. The only kei car to have exceeded this limit is the Caterham 7 160, a lightweight British sports car that was not expected to qualify as a kei car, though it is small enough (in dimensions and displacement) to fit the regulations. Its engine is rated at —since that is how the car is Homologation in the United Kingdom, Japanese authorities told the importer that its power should remain unchanged. The Japan Automobile Manufacturers Association also self-imposes a speed limit of for kei cars.

In a rare example of an overseas mass-produced model being sold as a kei car in Japan, a kei version of the Smart Fortwo (called the Smart K) was sold in Japan by Yanase from 2001 to 2004. The Smart K used revised rear fenders and reduced tire dimensions and track width to conform to kei regulations. The model was not a success, and sold the fewest examples of a kei car when it was marketed.

The Suzuki Wagon R was the best-selling kei car in Japan between calendar years 1996 and 2011, except in 2003, when the Daihatsu Move outsold the Wagon R. Starting in 2011, Toyota entered the kei car market for the first time. The resulting Toyota Pixis Space, a rebadged Daihatsu Move Conte, was expected to increase competition in that market. Nissan and Mitsubishi began to jointly produce the Mitsubishi eK (also sold as the Nissan Dayz and formerly the Nissan Otti). Honda's kei car lineup—the Honda N-One, N-Box, and Honda N-WGN—accounts for around a quarter of its overall sales.