## 1 Introduction  
There is a strong relationship between the special transport sector and manufacturers of products that are bulky and heavy. Such products include electricity transformers, metal castings, aircraft components, and wind-generator parts. The manufacturers of these products require the means to transport larger and heavier loads. An item's weight or maximum dimensions are often determined by the transport's constraints rather than manufacturing capacity. The infrastructure may determine the maximum loads that vehicles that are allowed to carry. The infrastructure includes the roads, regulations, capacity of roads or canals, or the load bearing capacity of vehicles [1; 2]. Some types of loads are transported by water to minimize traffic congestion and disruption on the roads [3]. This occurs particularly when enterprises have convenient access to water. Not all countries have long, internal waterways, such as Europe's Rhine and Garonne rivers. Therefore, most special loads in such countries are transported by road [4]. The safety of trailers as they travel around curves has been analyzed extensively previously. The effect of axle spacing, the load and the height of the center of gravity height on heavy trucks' stability and handling properties have been studied [5; 6; 7; 8]. Other works [9; 10; 11; 12] have revealed significant influence of loading and suspension stiffness on tractor-semitrailer yaw stability. That revelation involved theoretical models, simulations by computer, and full-scale tests. The theoretical transversal acceleration of a truck as it enters a horizontal curve is commonly calculated as follows [13]:  
\[a_{T}=\frac{v^{2}}{g\cdot R}\pm k \tag{1}\]  
With \(g\) for the acceleration of gravity, \(v\) as the truck's speed, \(R\) as the radius of the curve, and \(k\) as the side-slope. However, the equation does not include several other factors that affect the truck in actual operating conditions. These include the force of the wind and the slope of the road. The authors discovered that the lateral acceleration of a 5-axle trailer briefly exceeded the expected values. An earlier study [14] found that the rollover threshold for various articulated vehicles ranges from 0.33 to 0.54 g, according to the dimensions and weight of the load. Other authors [15] determined when the vehicle might roll over and developed a dynamic rollover threshold. The critical lateral accelerations that these authors determined range from 0.28 to 0.42 g according to the height of the center of gravity (CoG). These are in agreement with the values that earlier studies have provided [14; 16; 17]. In addition, the British Standard [18] describes blocking and lashing procedures for securing loads. It established coefficients of 0.8 for forward direction (braking) and 0.5 for backward (acceleration) and sideways (turning) directions. It does not relate these coefficients to the speed or consider the inclination of the road or force of the wind. This means that the coefficients cover all of these phenomena. The aerodynamic forces on a truck affect the performance in various ways [19; 20; 21]. Forces acting on the side increase the roll instability like the lateral acceleration in curve driving does. Furthermore, the longitudinal force affects the speed and acceleration of the truck and, consequently, its fuel consumption [22]. When a standard heavy truck drives at a speed of 70 mph, 65% of its fuel consumption, it has been estimated, is used to overcome the aerodynamic force [23]. Aerodynamic forces usually have a significant effect on the stability of abnormal loads. These forces are caused by the truck's movement relative to the air. They emanate from the truck's body, the chassis, the suspension, the axles, the wheels, the trailer, the load, and the space between the truck and trailer or payload.