Iowa Agricultural Trucking Guide

The 25% Agricultural Weight Exception

Iowa provides a weight exception that matters in a state built on agriculture: trucks transporting raw agricultural products can operate up to 25% over their registration weight. This is one of the most generous agricultural weight exceptions in the Midwest.

How It Works

Example Calculation

This exception applies to gross vehicle weight. Individual axle weights must still comply with bridge formula requirements to avoid structural damage. The exception does not override posted weight restrictions on bridges or spring-thaw-restricted roads.

Seasonal Freight Calendar

Iowa agricultural freight follows predictable seasonal patterns:

Harvest Season (September-November)

Harvest is the peak demand period. Grain trucks flood county roads heading to elevators, bins, and rail terminals. Key facts:

• Combine traffic on rural highways — slow-moving equipment with wide headers
• Grain trucks entering from field access roads, often without full stops
• Dust from harvest operations can reduce visibility
• Extended hours of operation as farmers push to complete harvest before weather turns
• Elevator wait times can exceed 2-3 hours during peak harvest

Planting Season (March-May)

Spring planting creates a different freight pattern:

• Anhydrous ammonia is the big one — pressurized tanks of anhydrous ammonia move from terminals to farm application equipment. This is hazmat freight that requires PHMSA registration, placarding, and proper endorsements.
• Fertilizer (dry and liquid) moves in bulk from terminals to farms
• Seed shipments move from distribution centers to retail locations and farms
• Spring thaw restrictions may limit secondary road access (see Iowa Spring Thaw Restrictions)

Anhydrous Ammonia Transport

Anhydrous ammonia is one of the most common hazmat loads in Iowa. It is used as a nitrogen fertilizer and is transported as a compressed liquefied gas.

Requirements

Safety Considerations

Anhydrous ammonia is corrosive and toxic. A release can be fatal. Carriers hauling NH3 need:

• Equipment inspection before every load
• Proper valve and fitting maintenance
• Emergency shutoff knowledge and drills
• PPE including respiratory protection
• Route planning that avoids populated areas where possible

Livestock Hauling

Iowa is a major livestock state, and hauling live animals comes with specific considerations:

Regulations

• 28-hour rule: livestock must be unloaded for feed, water, and rest after 28 hours of consecutive transport
• Animal welfare inspections at destination
• Biosecurity protocols between loads — trailers must be cleaned and disinfected
• Loading density requirements based on animal size and weather conditions

Insurance Considerations

Livestock mortality coverage is separate from standard cargo insurance. The value of a loaded livestock trailer can be substantial — a trailer of feeder cattle can be worth $200,000 or more. Adequate cargo limits are essential.

Grain Elevator Routing

Grain elevators are the destinations that drive harvest-season trucking in Iowa. They sit at railroad junctions, along rivers, and in small towns throughout the state. Key routing considerations:

• Many elevators are accessed via county roads that may have weight restrictions
• Queuing space is limited — trucks waiting to unload may line up on adjacent roads
• Scale access can create bottlenecks at small elevators
• Rail-served elevators may have grade crossings that affect routing

Planning Tips

1. Call ahead to confirm wait times during peak harvest
2. Check county road weight postings before routing
3. Know your alternate elevators in case primary is backed up
4. Schedule early morning or late evening unloading to avoid peak waits

Construction Materials HOS Exception

Iowa provides a construction materials HOS exception that benefits agricultural-adjacent operations:

This exception applies to drivers transporting construction materials within Iowa. Given that much of Iowa’s construction involves rural road projects in agricultural areas, this exception overlaps with agricultural hauling patterns.

Insurance for Agricultural Operations

Agricultural hauling in Iowa creates specific insurance needs:

• Cargo coverage should match the commodity value — grain prices fluctuate, and a full hopper can be worth $50,000+
• Hazmat coverage is required for anhydrous ammonia and other agricultural chemicals
• Livestock mortality for live animal hauling
• Seasonal volume — some carriers operate primarily during harvest, which affects policy structure

Iowa has the lowest state insurance minimums in the Midwest ($20,000/$40,000/$15,000). One agricultural accident — a grain truck collision, an anhydrous ammonia release, or a livestock trailer rollover — would exceed those limits instantly. RMS recommends $1,000,000 CSL minimum.

For agricultural trucking insurance in Iowa, contact RMS at (208) 800-0640.