Hawaii Axle Weight Limits

Maximum Legal Weight Allowed

The total gross weight imposed on the road surface by any group of two or more consecutive axles on a vehicle or combination axles on a vehicle or combination of vehicles shall not exceed the following when the distance between the first and last axles of the group under consideration is:

• Less than 42 inches - 24,000 pounds;
• 42 inches but less than 6 feet - 34,000 pounds
• 6 feet and over - W=500(LN/(N - 1) + 12N + 36),

This applies to interstate highways.

W = maximum weight in pounds carried on any group of two or more axles computed to the nearest 500 pounds;
L = distance in feet between the extremes of any group of two or more consecutive axles, to the nearest foot and
N = number of axles in group under consideration;

Provided that 2 consecutive sets of tandem axles may carry a gross load of 34,000 pounds each providing the overall distance between the first and last axles of such consecutive sets of tandem axles is 36 feet or more and provided the overall gross weight does not exceed 80,800 pounds.

W = 880(L + 40)

This applies to non-interstate highways.

W = maximum weight in pounds rounded to the nearest 500 pounds; and
L = distance in feet between first and last axles of the vehicle or combination of vehicles.

No vehicle or combination of vehicles shall be used or operated on any state highway with a load upon any single or tandem axle or combination of axles which exceeds the carrying capacity of the axles specified by the manufacturer, or with a total weight in excess of its designed capacity as indicated by its designed gross vehicle weights or gross combination weights. 

• Axles placed in the same transverse plane which are closer than 42 inches shall be considered as one axle.
• The total gross weight imposed upon the public road, street or highway by any single axle shall not exceed 24,000 pounds.
• The total gross weight imposed upon the road surface by any one wheel, either single or dual mounting, shall not exceed 12,000 pounds.
• In addition to the foregoing limitations on weight, no vehicle shall be operated over a bridge if the gross weight of the vehicle exceeds the posted load limitations of the bridge, unless the owner first secures a written permit from the department. 

Maximum Permitted Weight

The district engineer may issue a permit for overloads, provided the following load conditions are not exceeded:

The actual axle load imposed upon the pavement shall not exceed 48,000 pounds in the case of a single axle or 84,000 pounds for a tandem axle. On structures the axle load shall not exceed the allowable load taken from the following table:

• Axle Width (Tread Width) - 6 feet; Single Axle - 36,000 pounds; Tandem Axle - 48,000 pounds;
• Axle Width (Tread Width) - 7 feet; Single Axle - 39,000 pounds; Tandem Axle - 52,000 pounds;
• Axle Width (Tread Width) - 8 feet; Single Axle - 42,000 pounds; Tandem Axle - 56,000 pounds;
• Axle Width (Tread Width) - 9 feet; Single Axle - 45,000 pounds; Tandem Axle - 60,000 pounds;
• Axle Width (Tread Width) - 10 feet; Single Axle - 48,000 pounds; Tandem Axle - 64,000 pounds.

The wheel load per tire shall not exceed 12,000 pounds.

"Tread Width" is the distance between the centerlines of the two tires on the same axles. For dual tires, it is the distance between the centers of the two sets of tires. For multiple tires on the same axle, it is the distance between the centers of the two sets of tires. For multiple tires on the same axle, it is the distance between the centers of the outer two tires on each end.

A single axle is a single continuous transverse shaft or split transverse shafts connecting the wheels of a vehicle or a group of two or more transverse shafts connecting the wheels of a vehicle which may be on separate vertical transverse planes which are less than 42 inches apart.

A tandem axle is a combination of two consecutive single axles as defined above which are less than 6 feet but greater than 42 inches apart.

Source of information: https://hidot.hawaii.gov/highways/files/2012/12/HAR19-104.pdf