Big rigs, tractor trailer and 18-wheeler trucks fill Pennsylvania highways and can present a real danger to motorists.  Because of their size alone, commercial trucks are responsible for causing some of the most serious injuries and fatalities in the Commonwealth.  The trucking industry revolves around getting a load to a destination in a timely manner and that sometimes leads truck drivers to travel at unsafe speeds or to make other unsafe and unwise decisions.  Another danger can present itself when a truck is overloaded with freight.  When a truck is too heavy, it cannot successfully carry and balance its load and is unable to stop or maneuver as well as it should.  Though most truck drivers are safe and efficient on the roadways, it is important for Pennsylvania motorists to remember that large trucks need more room on the highway than private passenger vehicles and one should never crowd a large truck or follow too closely.