The paper present a new alert system to inform drivers of a risk of grip loss. The assessment was carried out by comparing drivers’ speed during three steps: a reference stage, a general alert and a individual alert. It was shown that the first sign has a positive effect. This effect is reflected by lower driving speeds (more important in the situation "wet road") during which the sign is activated. Thus, it appears that the speed reduction during this phase is increased by 5 km/h compared with the same conditions of the reference phase. This observation is made for all points of speed measurements. Assessing the impact of individual alert message did not demonstrate a significant reduction in driving speeds for the part of drivers who has been warned against that which has not been. A complementary study on vehicles driving within platoons showed that it could not be attributed any noticeable effect of the speed alert system on the rear-end collision risk indicator.
