Four wheel drive vehicles have superior performance in driving safety on mountainous terrain and snowy roads. They have usually in the past, however, been inferior to conventional vehicles in stability in the high speed range, quietness and riding comfort, and maneuvering ease, accompanied by disadvantages in price and fuel economy.

The growth of motorization has brought recently an increasing number of motorists who wish to drive safely and comfortably under various circumstances. The four wheel drive vehicle we introduce here (referred to hereafter as NC4V-A) is an answer to such a demand in the market;​ it is designed on the basis of a front wheel drive car and has a part-time 4WD system, with which the driver can switch from FWD to 4WD and vice versa without stopping the car. This new model of four wheel drive vehicle is provided with greater security in driving on hilly, snowy or rainy roads, and also with directional stability, quietness and riding comfort in high speed driving on ordinary paved roads, comparable with those of conventional passenger vehicles. Price and fuel economy also compare well with other conventional cars.

An automatic transmission model is also available, in which instantaneous and easy switching of the drive mode is possible with the push button control, on any road and at any speed. It enables the driver to selec the drive mode freely, and makes possible a safer car, which can be easily driven in various circumstances even by an unskilled driver.

On the same basis of design concept, a cab-over type mini car, wagon and truck modele, with part-time 4WD system (referred to hereafter as NC4V-B) was developed as a derivative of the RWD mini car, which is propelled by a 550 cc engine.

In this paper, construction of these "New Concept Four-Wheel-Drive Vehicles" is outlined, and their driveability on rough roads, stability, controllability, and crashworthiness are discussed, as well as fuel economy and quietness.