There is a product that has increased sales since about last summer.
It is "Hands-free" device that can be talked over the telephone without having the cellular phone in the hand.
There are two kinds of popular devices. One is "Earphone type" that connects the code in which the earphone ties to the mike with the cellular phone.
Another is "Speaker type" that sets up the speaker and the mike in the car.
The biggest reason to support good sales is revision the Road Traffic Law enforced on November 1, 2004.
This law prohibited the use of the cellular phone while driving, and installed the penal regulations to the transgressor.
Revision the Road Traffic Law prohibited not only the telephone call by the cellular phone while driving but also the gaze at the screen for the mail sending and receiving.
This law excluded the telephone call of hands-free that did not become an one hand driving from the restriction.
The National Police Agency explains, "Hands-free makes the hand free by the telephone call by the cellular phone. There is no necessity for doing a restriction similar to the act with the cellular phone by the hand in the present stage because the stability of the driving operation by hands-free is different from a usual conversation".
Then, how much influence does the driver receive when talking over the telephone with hands-free while driving?
Mr. Catsraho Suzuki who was the assistant professor of Mechanical Engineering Section of Daido Institute of Technology experimented for 24 men and women.
Prof. Suzuki measured reactive time to the sight stimulation based on three conditions.
Three states are in a usual driving, in a driving under telephone call with the cellular phone, and in a driving under telephone call with a hands-free cellular phone.
There was no difference between three states about the reaction to the turning on the lamp in the front in the driving simulator operation experiment that the driver pushed the button when the lamp lit.
And, reactive time of the driver of "Talk over the telephone with the cellular phone" was 2.2 times as slow as that of a driver "Did not talk over the telephone" about the reaction to the turning on the lamp put on the position of 90 degrees in the right and 90 degrees in the left.
Moreover, reactive time of the driver of "Talk over the telephone hands-free" was 1.7 times as slow as that of a driver "Did not talk over the telephone".
Assistant professor Suzuki speaks, "It cannot be judged that hands-free is dangerous only in this experiment result". However, he is pointing out, "When it is assumed that a dangerous event occurred while talking over the telephone, reactive time of the driver of 'Talk over the telephone hands-free' has been delayed compared with the driver of usual 'Do not talk over the telephone'".
Such a research is executed in every country in the world.
The major damage insurance company Direct Line in Britain experimented two years ago the measurement of reactive time to step on the brake in four states of "Drove usually" and "Drove of the telephone call with the cellular phone. " , "Drove of the telephone call with hands-free", and "Driving under the influence of liquor".
Reactive time of hands-free was slower than that of the driving under the influence of liquor according to the experiment.
The evaluation of hands-free is various now. It is in the midst of verifying of every country in the world.
However, there are a lot of people who have misunderstood as the product for which safety is secured because there is a product sold by the watchword with "It is possible to drive safely with the steering wheel gripped".
Assistant professor Suzuki rouses watching out , saying that "It should not be thought it is thorough for driving if it is a cellular phone of hands-free. Because there is a possibility that an obstacle view peripheral is not noticed easily, the driver should be deep watching out and confirm it".
And, he speaks that a psychological load of the speaker type seems to be less than that of the earphone type.
Assistant professor Suzuki is advising, "After confirming tone quality, you should buy it when you choose the model of the speaker type".