Side Winds
Vehicles with high flat sides, such as Furniture trucks and Double Deck trailers, are extremely susceptible to the effects of cross wind (wind blowing onto the side of the vehicle). In conditions of extreme cross wind, road controlling authorities may issue strong wind warnings for some stretches of road. When these are issued take note, and if the warning includes advice not to travel over a particular area of road – don’t. Remember also that your vehicle will generate its own wind as it moves along the road. The faster you go the greater the wind forces generated will be. These forces can be sufficient to blow motorcyclists over and buffet other vehicles to a point that a driver losses control, so you need to be considerate of other road users and slow down.
Speed
The effect of speed on the cornering ability, braking distance and impact forces acting on a vehicle increase as the speed increase. Cornering forces don’t double when the vehicle speed doubles, they increase by four times.
This effect is highlighted in the following diagram:
The arrow in the left-most illustration represents the overturning force acting on a truck in a 30 Km/h (18.6mph) corner. If the same truck is driven through the same corner at 60 Km/h (37.2mph), the overturning forces will be four times higher, represented by the arrow in the middle illustration. If the truck is now driven through the same corner at 90 Km/h (55.9mph) the overturning forces will be nine times higher than at 30 Km/h, as in the third illustration.
Gravity
Gravity creates a force that, in simple terms, attracts everything towards the centre of the centre of the earth.
The force is measured as weight and means that a person weighing 90 Kilograms (14.1 stone) and a truck weighing 15,000 Kg are both attracted towards the centre of the earth with the same speed of acceleration. If both were free to fall they would accelerate at the same rate, called 1 gravity (1g).
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