http://www.fmcsa.dot.gov/rules-regulations/truck/vehicle/cs-policy.htm said:
& sect;393.128 What are the rules for securing automobiles, light trucks and vans?
Applicability. The rules in this section apply to the transportation of automobiles, light trucks, and vans which individually weigh 4,536 kg. (10,000 lbs) or less. Vehicles which individually are heavier than 4,536 kg (10,000 lbs) must be secured in accordance with the provisions of & sect;393.130 of this part.
Securement of automobiles, light trucks, and vans.
Automobiles, light trucks, and vans must be restrained at both the front and rear to prevent lateral, forward, rearward, and vertical movement using a minimum of two tiedowns.
Tiedowns that are designed to be affixed to the structure of the automobile, light truck, or van must use the mounting points on those vehicles that have been specifically designed for that purpose.
Tiedowns that are designed to fit over or around the wheels of an automobile, light truck, or van must provide restraint in the lateral, longitudinal and vertical directions.
Edge protectors are not required for synthetic webbing at points where the webbing comes in contact with the tires.
& sect;393.130 What are the rules for securing heavy vehicles, equipment and machinery?
Applicability. The rules in this section apply to the transportation of heavy vehicles, equipment and machinery which operate on wheels or tracks, such as front end loaders, bulldozers, tractors, and power shovels and which individually weigh 4,536 kg (10,000 lbs) or more. Vehicles, equipment and machinery which is lighter than 4,536 kg (10,000 lbs) may also be secured in accordance with the provisions of this section, with & sect;393.128, or in accordance with the provisions of & sect; & sect;393.100 through 393.114.
Preparation of equipment being transported.
Accessory equipment, such as hydraulic shovels, must be completely lowered and secured to the vehicle.
Articulated vehicles shall be restrained in a manner that prevents articulation while in transit.
Securement of heavy vehicles, equipment ormachinery with crawler tracks or wheels.
In addition to the requirements of paragraph (b) of this section, heavy equipment or machinery with crawler tracks or wheels must be restrained against movement in the lateral, forward, rearward, and vertical direction using a minimum of four tiedowns.
Each of the tiedowns must be affixed as close as practicable to the front and rear of the vehicle, or mounting points on the vehicle that have been specifically designed for that purpose.
& sect;393.132 What are the rules for securing flattened or crushed vehicles?
Applicability. The rules in this section apply to the transportation of vehicles such as automobiles, light trucks, and vans that have been flattened or crushed.
Prohibition on the use of synthetic webbing. The use of synthetic webbing to secure flattened or crushed vehicles is prohibited.
Securement of flattened or crushed vehicles. Flattened or crushed vehicles must be transported on vehicles which have:
Containment walls or comparable means on four sides which extend to the full height of the load and which block against movement of the cargo in the forward, rearward and lateral directions; or
Containment walls or comparable means on three sides which extend to the full height of the load and which block against movement of the cargo in the forward, rearward and the lateral direction for which there is no containment wall or comparable means, and
A minimum of two tiedowns are required per vehicle stack; or
Containment walls on two sides which extend to the full height of the load and which block against movement of the cargo in the forward and rearward directions, and
A minimum of three tiedowns are required per vehicle stack; or
A minimum of four tiedowns per vehicle stack.
In addition to the requirements of paragraphs (c)(2), (3), and (4), the following rules must be satisfied:
Vehicles used to transport flattened or crushed vehicles must be equipped with a means to prevent loose parts from falling from all four sides of the vehicle which extends to the full height of the cargo.
The means used to contain loose parts may consist of structural walls, sides or sideboards, or suitable covering material, alone or in combinations.
The use of synthetic material for containment of loose parts is permitted.