Big trucks are the heaviest trucks allowed on roads, and are generally used for long-distance journeys. A truck is a motor vehicle for transporting goods. The word "truck" comes from the Greek "trochos" that means a "wheel."
Road damage increases very quickly with axle weight or truck weight divided by the number of axles. In many countries with good quality roads, a 6-axle truck is permitted to have a maximum weight of 50,000 kg.
Big trucks are a major source of smog (smoke + fog), of poisonous chemical contamination, and of fine particle soot. The federal government rates any automobile above 8500 pounds as a "heavy-duty" truck, and that includes large pickup trucks and many other types. Big trucks are legally permitted to emit as much pollution as a dozen of cars, but in reality, many big trucks produce as much pollution as 150 cars.
Urban areas suffer the most because of big trucks and buses. In case of an accident, big trucks, because of their size, can cause the worst damage to occupants in a car. Hence, it is natural that many drivers are frightened when they must share a road with big trucks. According to AAA (American Automobile Association), people in passenger cars comprise 98% of deaths in deadly two-vehicle crashes involving a car and a truck weighing over 10,000 pounds.
Big trucks produce air turbulence that can suck another vehicle towards them or push it out. This means that a vehicle needs to have sufficiently large space alongside between a truck and itself.
In spite of all these issues, it is important to note that truck drivers are trained. Statistically their safety record is satisfactory and is getting better. According to the Ontario Trucking Association website, truck drivers of commercial trucks are the safest drivers and motor vehicles on roads. Actually, trucks are involved in 20% fewer accidents at present than they were 10 years ago.