The trucks that ship cars are typically on the road a lot, because they are making use of their most expensive asset: the truck and trailer. The more a car shipping company keeps its trucks on the road and running full, the lower the price of car shipping. However, that makes delays more likely than if they were not on the road as much. Anything that delays the car carrier, such as a late customer, inaccurate paperwork, a flat tire, or long weigh station lines, can delay your pick-up or delivery.
The risk of delays makes it nearly impossible for a car shipping company to provide you with an exact pick-up or delivery date. (If they do, get it in writing and be sure it clearly states any remedy if the date is not met.) Most car shipping companies provide a 3-day window for pick-up and delivery. Plus, they should inform you ahead of time if there are any delays.