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Most of road accidents are caused by human factors. However, there are other factors involved in the occurrence of vehicular crashes, such as the physical condition of the road and vehicle itself. In order to increase road safety is essential to fully understand the interaction of those factors on vehicle's dynamic behavior, especially on heavy vehicles due to their greater mass, dimensions and potential damage that can provoke. This document presents information about the effect of some road surface irregularities on dynamic behavior of a three-axle heavy vehicle, based on a road with an ideally good condition (baseline). To do that, a numerical simulation model that includes both vehicle and road is used. It is able, at some degree, to simulate surface road conditions, such as potholes, friction coefficients at height levels of adjacent lanes.

In recent years, supersingle tires have been introduced in order to replace dual tires. In some countries such replacement is not a straight forward issue due to either lack of knowledge on its mechanical behavior or because their regulations do not consider such tire configuration. Usually, it is assumed that the force transmitted by dual single tires onto the roadway surface is evenly distributed and the contact pressure is quite similar to the tire's inflation pressure, although studies in this topic have shown that these assumptions are not realistic. Therefore, damage produced by supersingle tires is a main concern for road and transportation authorities. In order to obtain information on supersingle tires' behavior, a lab experimental assessment was carried out.

The relationship between road geometric design and vehicles moving along it should be in a harmonic way in order to reduce the risk of accident occurrence. As a safety issue, the accident black spot analysis can lead to improvements in traffic signaling and/or to changes to the conflictive roadway section. This paper shows the applicability of the vehicle's dynamic behavior simulation as a complementary tool for evaluating geometrical modifications of roadway sections. A simplified example is described using a typical heavy vehicle, which follows a roadway section under two scenarios, one with an unchanged path and other with some modifications in order to increase safety. Results showed that vehicle's dynamic simulation can offer a detailed perspective of the vehicle's behavior to identify the effectiveness of the proposed changes before they are applied in the practice.

Heavy vehicles commonly use dual tires on their load and traction axles. As the only vehicle component involved in force transmission to the road, the tire is an important element in the road damage process. In this context, two factors involved are the tire's supported load and inflation pressure. Traditional practical assumptions are that each of the tires in dual arrangement supports the same load, and that the contact patch pressure is very similar to the tire's inflation pressure. To provide data about the load distribution and contact pressure in the tire's contact patch, a lab experimental study was carried out. For that, a lab device was used to determine the static load and pressure in the contact patch, using three different sets of heavy duty radial tires subjected to several combinations of supported load and inflation pressure.

The effect of wheelbase variation on the rollover threshold for a three axles' unit heavy-duty vehicle, is presented in this work. For this, a vehicle dynamic behavior simulation model to analyze lateral stability is used. Also, the concept of load distribution on rear axles and the relationship with geometric definition of wheelbase is incorporated, and so, the effect on handling characteristics is analyzed. Besides, results of the combined effect considering stiffness suspension in front and rear axles on resulting handling is included, according wheelbase variation. Results suggest a wheelbase value in which the vehicle highest rollover threshold is obtained.