Over-dimensional shipments refers to any freight that is over-sized, over-length, over-width, or over-weight. These types of shipments require special permits from the state to be moved, especially over-weight freight, and specialized training to ensure safe transport for both the freight and for other motorists on the road.
In addition to special permits and training, over-dimensional freight also requires additional logistical planning as things like bridges and over-passes can present an obstacle not faced by other vehicles. This requires additional planning for routes that won’t present potentially hazardous obstacles, as well as making sure that escort vehicles will be able to monitor the progress of the carrier.