Fleet
Federal bridge formula weight screen
Your inputs
Complete only the fields for your selected method. Use one consistent job or reporting period. Use zero for a known zero amount only when the field permits it. Missing costs and market rates are not added automatically. Currency selection labels amounts; it does not convert exchange rates.
How this calculation works
W = 500 × round(L × N / (N − 1) + 12N + 36); L is outer spacing in feet. Apply the 20,000 lb single-axle group, 34,000 lb tandem group, consecutive-tandem exception and 80,000 lb gross limit separately.
For ordinary operation on U.S. Interstate highways under general federal limits. Supply measured axle-center spacings and per-axle weights for the loaded configuration. Count only eligible load-bearing axles. This tool does not decide whether special axles qualify. Excludes posted bridge limits, state-specific exceptions, axle and tire ratings, permits and vehicle classifications. Results do not authorize travel. Use your own records for the same scope and period. Example figures are illustrative, not industry benchmarks. Results exclude income taxes and any cost you have not entered. Check the result before pricing work or committing resources.
What information do I need?
Use records for the same job, equipment or accounting period. Only the fields for your selected entry method are required. An unknown amount is not zero.
Input definitions and where to find them
- Axles in order from front to rear: Enter matching rows from your records; add or remove rows as needed.
- Measured weight on this axle (lb): Use the matching measured quantity, time log, schedule or clearly stated estimate. Zero means intentionally none; an unknown amount is not zero.
- Distance from preceding axle center (enter zero on first axle) (in): Enter zero for the first axle. For every later axle, enter center-to-center spacing from the axle immediately ahead. This screen uses whole inches.
Use the Where to find this value controls beside the inputs for available work-it-out helpers. Estimates remain your assumptions; a helper does not verify the source figures.
Worked example
Example amounts use US dollars (USD).
Example answer: Federal weight screening result is One or more screened limits exceeded for the illustrative inputs below.
Example inputs
- Axles in order from front to rear
- Measured weight on this axle: 12,000 lb
- Distance from preceding axle center (enter zero on first axle): 0 in
- Measured weight on this axle: 17,000 lb
- Distance from preceding axle center (enter zero on first axle): 192 in
- Measured weight on this axle: 17,000 lb
- Distance from preceding axle center (enter zero on first axle): 48 in
- Measured weight on this axle: 17,000 lb
- Distance from preceding axle center (enter zero on first axle): 324 in
- Measured weight on this axle: 17,000 lb
- Distance from preceding axle center (enter zero on first axle): 48 in
- Federal weight screening result
- One or more screened limits exceeded
- Entered gross weight
- 80,000 lb
- General federal gross limit
- 80,000 lb
- Gross limit minus entered weight
- 0 lb
- Smallest margin across gross and axle groups
- -2,500 lb
- Axle groups above a screened limit
- 1 groups
- Check current bridge postings, axle ratings, applicable state rules and permits with the responsible authorities.
These illustrative values are not recommended rates or industry averages. Replace every example input with your own figures.
Use the result well
Inputs come from your own records and stated assumptions; no rates or legal limits are looked up.
Review the entered assumptions and calculator limits before using these results.