Heavy trucks, whether tractor-trailers, construction vehicles or garbage haulers, are involved in many serious traffic accidents due to their large weight, high centers of gravity, decreased visibility, poor handling and reduced braking efficiency. In addition, articulated tractor-trailers are subject to additional problems such as jack-knife and trailer sway instabilities. Truck tires and brakes also behave differently from those of passenger cars and require special consideration. Other truck issues that are frequently encountered include driver fatigue and clearance problems when driving through underpasses.