The Bill of Lading or BOL, is the most important document in the auto transport process. It serves as the offical record of your vehicle's condition at pickup & delivery and the legal proof that a transport was completed. 

When the carrier arrives to pickup your vehicle, they will do a walk around inspection and document any pre-existing damage on the vehicle. This could be scratches, dents, chips or just simply notes the driver makes on the bill of lading before taking possession of the vehicle. The carrier & the customer will need to sign the BOL at pickup, confirming the vehicle's condition in that moment. 

The same process happens at delivery. The carrier & receiving party will inspect the vehicle & note any changes in condition on the delivery copy of the BOL. If any damage did occured during transport, this is where it is documented & is often the only evidence an insurance company is interested in for a claim. 

That is why the BOL is so important, without it there is a huge burden to prove that any damage occured DURING the transport, rather then before or after the vehicle was delivered. An insurer cannot process a legitimate claim without it. 

I recommend always doing the inspection in daylight when possible, take your own photos on pickup & delivery alongside the carriers inspection & never signing the BOL on delivery if there is new damage that is not documented on the form first. 

The BOL also serves as the proof that the transport occured. It is often required to be submitted to a professional broker to release payment. Having a BOL submission requirement for payment incentivizes drivers to complete the BOL properly.