DOT Weight and Size Limit Regulations 1 — Questions and Answers
Question 1: What is the maximum gross vehicle weight (GVW) allowed on the Interstate highway system without a special permit?
- 73,280 lbs
- 80,000 lbs (Correct answer)
- 85,000 lbs
- 90,000 lbs
Correct answer: 80,000 lbs
Federal law (23 USC 127) limits gross vehicle weight on Interstate highways to 80,000 pounds absent a special overweight permit.
Question 2: What is the federal maximum single axle weight limit on Interstate highways?
- 18,000 lbs
- 19,500 lbs
- 20,000 lbs (Correct answer)
- 22,000 lbs
Correct answer: 20,000 lbs
23 USC 127 establishes a maximum single axle weight of 20,000 pounds on the Interstate highway system.
Question 3: What is the federal maximum tandem axle weight limit on the Interstate highway system?
- 32,000 lbs
- 33,000 lbs
- 34,000 lbs (Correct answer)
- 36,000 lbs
Correct answer: 34,000 lbs
Federal law caps tandem axle weight at 34,000 pounds; tandem axles are typically defined as two axles spaced 40 inches or less apart.
Question 4: What is the maximum vehicle width permitted on federal-aid highways under federal regulations?
- 96 inches
- 100 inches
- 102 inches (Correct answer)
- 108 inches
Correct answer: 102 inches
Federal regulations allow a maximum vehicle body width of 102 inches (8.5 feet) on federal-aid highways, not counting safety devices.
Question 5: Bridge Formula B is primarily used by DOT inspectors to:
- Determine speed limits on bridges
- Calculate maximum allowable axle-group weight based on axle spacing (Correct answer)
- Measure minimum bridge clearance heights
- Rate bridge structural load capacity
Correct answer: Calculate maximum allowable axle-group weight based on axle spacing
Bridge Formula B limits the maximum weight on any group of two or more consecutive axles based on the distance between them, protecting bridges from overload.
Question 6: A commercial vehicle weighing 80,001 lbs GVW on the Interstate requires which of the following before it may legally operate?
- A FMCSA safety rating waiver
- A special oversize/overweight permit (Correct answer)
- A USDOT number upgrade
- A revised bill of lading only
Correct answer: A special oversize/overweight permit
Any vehicle exceeding the 80,000-lb federal GVW limit must obtain a special overweight permit from the appropriate state authority before operating.
Question 7: Which federal agency has primary authority over size and weight regulations on federal-aid highways?
- FMCSA
- NHTSA
- FHWA (Correct answer)
- TSA
Correct answer: FHWA
The Federal Highway Administration (FHWA) holds primary authority over vehicle size and weight standards on federal-aid highways under 23 USC 127.
DOT Weight and Size Limit Regulations 1
What is the maximum gross vehicle weight (GVW) allowed on the Interstate highway system without a special permit?