A lot of these big rigs are well taken care of and driven carefully. The engines work hard but are not abused. There is no way to compare the life cycle of one of these trucks to the average passenger car. In our fleet of in town diesel deliver trucks that experience stop and go driving there is no such thing as an engine that will hit a million miles. These trucks are driven hard, fast and slow, heavy and light and hardly ever see steady use. The drivers are always pressed to go faster, make more stops and get stuck in all the traffic jams. The more they deliver and pickup the more they get paid. They don't spare the horses. The owner of the fleet is always looking for something in maintenance to make these truck last longer and run better but he never tells the drivers to take it ez. As long as the trucks are making money, they will continue to get driven hard. And what we are doing for oil, changes and filters probably has no value to long haul trucks or passenger cars.