The paper presents a driver model, which can be used in a computer simulation of a curved ride of a car. The identification of the driver parameters consisted in a comparison of the results of computer calculations obtained for the driver-vehicle-environment model with different driver data sets with test results of the double lane-change manoeuvre (Standard No. ISO/TR 3888:1975, International Organization for Standardization [ISO], 1975) and the wind gust manoeuvre. The optimisation method allows to choose for each real driver a set of driver model parameters for which the differences between test and calculation results are smallest. The presented driver model can be used in investigating the driver-vehicle control system, which allows to adapt the car construction to the psychophysical characteristics of a driver.

Friction properties of the road surface have a great influence on the safety of automobile motion. These properties are characterized by the tyre-to-road adhesion coefficient, which is measured during the routine and acceptance investigations of roads. In the paper, the method of measurement of this coefficient is presented. For investigation of the tyre-to-road adhesion coefficient the special measurement system was developed. The main part of the system is dynamometer trailer, which makes it possible to measure the friction force between tyre and road surface. The adhesion coefficient as a quotient of the friction force and vertical load is a result of measurements. Additionally the system enables to determine the graph of the adhesion coefficient as a function of wheel slip ratio. In the paper a description of the measurement system and a principle of its operation are presented. Exemplary results of tyre-to-road adhesion coefficients measured on different roads are also presented. The results show many differences between these coefficients in dependence of road upper layer technology, degree of its wear, weather conditions, sliding velocity and others. The system originally designed for investigation of friction parameters of road surfaces can have much wider applications, for example in tyre investigations, for automotive experts, in the work of judgment witnesses and others.

The interaction between the driver and the vehicle plays a significant role in all problems of active safety. Various schemes for vehicle-driver-environment systems have been considered in many papers. Elaborated driver model is characterised by three parameters: Aim Point Distance, Response Delay and Steering Angle Gain. To reduce a danger and research cost for identification of the driver model parameters, instant of the road tests, a drum type test stand was used. The stand allows to simulate a curved ride of a car, for instance: the double lane change manoeuvre (ISO/TR 3888). The ride is controlled by a driver according to the changing road pictures presented simultaneously on the computer screen. Several drivers took part in the tests. The identification of the driver parameters consisted in comparison of the test results (diagrams of lateral position, steering angle, yaw velocity and lateral acceleration versus time) with the results of computer calculations obtained for the vehicle-driver-environment model with different driver data sets.

This paper presents a method of identifying the dynamic characteristics of tyres for non-steady-state conditions on the basis of road measurements on a vehicle. The side force acting on the tyre is presented as a function of not only the slip angle but also the slip angle derivative (i.e. the velocity of the change in the slip angle). Hence, the influence of the manoeuvre dynamics on the tyre characteristics and the difference between the characteristics obtained for steady-state conditions and the characteristics for non-steady-state conditions are shown. Also the results of computer simulations prepared for different types of tyre characteristics are presented in this paper. It is evident from the presented graphs that applying dynamic non-linear tyre characteristics for computer simulations instead of steady-state characteristics enables us to describe the real motion of a vehicle better.

Bezpieczeństwo czynne jest jednym z najważniejszych czynników decydujących o rozwoju współczesnych samochodów. Obecne pojazdy są coraz bezpieczniejsze, ale także zapewniają coraz lepsze osiągi. Warunki drogowe występujące podczas jazdy są często różne i zmienne, podobnie jak zmieniać się może rozkład masy na osie pojazdu w zależności od rozłożenia ładunku. Typowy samochód osobowy ma cztery koła, za pomocą których przenoszone są na drogę siły wzdłużne i poprzeczne. W niniejszym artykule pokazano wpływ rodzaju nawierzchni i warunków atmosferycznych na graniczne siły na kołach pojazdu. Do tego celu wykorzystano metodę Dynamic Square Method (DSM). Pozwala ona na wyznaczenie maksymalnych sił wzdłużnych na kołach pojazdu dla danego przyspieszenia poprzecznego. Metoda DSM zapewnia uzyskanie charakterystyk w postaci izolinii o stałych wartościach przyspieszeń poprzecznych uzyskiwanych dla konkretnych wartości sił wzdłużnych na kołach jezdnych. Charakterystyki mieszczą się w polu ograniczonym czworokątem, od którego prawdopodobnie wywodzi się nazwa metody. Analizując uzyskane charakterystyki można określić, jaki wpływ na wartości sił wzdłużnych na kołach pojazdu ma zmiana wartości współczynnika przyczepności przylgowej.