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Breath alcohol interlock systems are used in Europe and the U.S. for drunk driving offenders, and a certain effect has been revealed in the prevention of drunk driving. Nevertheless, problems remain to be solved with commercialized detectors, i.e., a person taking the breath alcohol test must strongly expire to the alcohol detector through a mouthpiece for every test, more over the determination of the breath alcohol concentration requires more than 5 seconds. The goal of this research is to develop a device that functions suitable and unobtrusive enough as the interlock system. For this purpose, a new alcohol detector, which does not require a long and hard blowing to the detector through a mouthpiece, has been investigated. In this paper, as a tool available on board, a contact free alcohol detector for the prevention of drunk driving has been developed.

In this study, a new practical design method (tool) for engine sound quality in a car interior is proposed. The tool can automatically create the target interior sound using the psychoacoustic index ‘powerfulness’ based on subjective tests. Moreover, it can calculate the intake noise characteristic to create the target interior sound and select the suitable intake specification from the prepared database. By using this method sound engineering can be easily and effectively carried out without manufacturing an experimental car.

The purpose of this study is to develop a method for analysis and evaluation of vehicle sound quality that replicates the human hearing sense. First, a method for analysis using a human hearing model was developed, and the results of the analysis were expressed as an image. Second, a method for objective evaluation of vehicle sound quality was developed, based on subjective evaluation tests, and the evaluation result was expressed as an image and number. These results reflect the properties of human hearing, enabling intuitive recognition of vehicle sound quality. Therefore, this is applicable to sound quality comparison and interior sound quality design.

The intermittent turbid noise, often generated in a vehicle passenger compartment during acceleration, makes passengers feel unpleasant. This type of noise is called a “rumble noise”. We developed a quantitative method of evaluating the rumble noise, which agreed with the hearing sense of human beings. In the first part of our study, the rumble evaluation process of human beings was modeled on the basis of hearing characteristics. Next, the rumble noises in the vehicle passenger compartments were analyzed in conformity with the model. The analysis showed that there were many types of amplitude modulation, each of which has a unique sense of unpleasantness. Subjective evaluation tests were then carried out to find quantitative relationships between many types of amplitude modulation and a sense of rumble. Finally, we developed a quantitative objective rating method for the rumble noise on the basis of the above findings.