Compaction Prevention: Controlled Traffic
alternative practice names:
Controlled Traffic Farming; CTF; Tramlines; Skip Rows
Controlled traffic (CT) is the practice of operating farm machinery over the same paths in the field year after year. GPS technology is utilized to guide machinery precisely along these designated paths, ensuring consistent traffic lanes. As a result, compaction is confined to a small proportion of the field, typically less than 25% of the soil surface. By limiting machinery traffic to specific lanes, less of the field is impacted by equipment and compaction, and the most severe compaction is limited to a small area of the field.
Wide-scale adoption of CT has not yet occurred in the U.S., although it is likely moving in this direction with the increasing acceptance and implementation of guidance systems.
When used, in what regions in the U.S. is the practice found:
Northwest, West, Upper Midwest, Southwest, Northeast, Southeast
FARM SIZE
When used, typically found on farms of the following sizes:
Over 500 cows

Practice Benefits
Improved efficiency: Controlled traffic allows machinery to operate more efficiently by confining the operation of product transport equipment to designated lanes.
Increased yields: Reducing compaction should lead to increased yields, as plants will be better able to access moisture, air, and nutrients in the soil profile.
Improved infiltration and drought resistance: Reducing soil compaction increases pore space, which supports better water infiltration and enhances the soil's water-holding capacity, improving drought resistance.

Implementation Insights
Site-specific or Farm-specific requirements

Soils prone to compaction: Controlled traffic is likely to have the most beneficial effect on fine-textured soils in wetter regions, but such site-specific recommendations need further research.
Reliance on custom work: The adoption of controlled traffic is probably most limited by the incompatibility of farm equipment (e.g., different wheel spacings between planters and harvesters). Therefore, it may be challenging for farmers relying on custom applicators or harvesters to implement.
Field layouts: The irregular shapes and sizes of many fields can complicate the establishment of consistent controlled traffic lanes.
Required Capital Expenditures (CapEx)

Auto-steer systems: Real-time kinemtaic (RTK) guidance systems provide centimeter-level accuracy, which is ideal for maintaining precise and consistent traffic lanes year after year. While RTK systems offer the highest accuracy, other GPS-based guidance systems with less precision (e.g., differential GPS or standard GPS) can also be used for CT. However, these systems may not maintain traffic lanes as consistently over time, potentially reducing the effectiveness of CT.
Equipment with similar wheelbases: Farms use machinery with varying wheelbases and working widths, making standardization for controlled traffic challenging. Implementing controlled traffic often requires new equipment to match swath and pass widths. However, this expense can be minimized by aligning new equipment purchases with the correct tire and swath widths during regular equipment turnover. Many farms are developing controlled traffic investment plans that fit their usual machinery replacement schedules, which can take six to seven years to fully implement. Ensuring compatibility across all farm equipment is essential for effective system functioning, often requiring several years to achieve.
Required Operational Expenditures (OpEx)

Removing compaction from CT zones: Removing compaction from CT zones will incur some costs during the crop cycle, especially when producers intend to continue growing crops in those areas.
Implementation Considerations

Training: Implementing controlled traffic requires a shift in mindset towards prioritizing soil health alongside changes in machinery and farm layout. Staff and consultants need training to consistently stay on wheel tracks, which improves with more education and understanding.
Guidance systems: Compatibility between different brands of guidance systems and drift between seasons requires careful attention when selecting guidance systems. RTK guidance is essential for maintaining precision across all equipment, which may necessitate additional training for employees. Dependence on satellite signals is also a consideration. Creating unseeded "tramlines" in the controlled traffic lanes can serve as a visual guide in case of signal disruption, ensuring the continued operation of equipment.
Crop rotation: When fields are rotated to another crop, considerations on how to alleviate compaction in drive lanes may take extra cost and effort.
Financial Considerations and Revenue Streams
FEDERAL COST-SHARE PROGRAM
Funding is available for this practice through USDA's Natural Resources Conservation Service (NRCS) Environmental Quality Incentives Program (EQIP) and the Conservation Stewardship Program (CSP).
Related EQIP Practice Standard: Controlled Traffic Farming (334).
Related CSP Enhancement: Controlled traffic farming to reduce compaction (E334A).
Notes:
Check with the local NRCS office on payment rates and practice requirements relevant to your location.
Additional Resources
Article: Controlled Traffic (Soil Quality for Environmental Health)
Report: Precision Agriculture in the Digital Era: Recent Adoption on U.S. Farms (USDA-ERS)
Video: Controlled Traffic Farming: What is CTF and how to Implement it on Your Farm (Terrain NRM)
Video: Farm Basics #1178 Controlled Traffic in Fields (AgPhD)
Website: Controlled Traffic Farming (NIAB)

Environmental Impacts
IMPROVES WATER QUALITY
Reducing compaction enables more water to infiltrate the soil, recharging groundwater and minimizing the transport of sediment and nutrients into nearby water bodies. While the direct linkage between compaction prevention technologies and specific water quality benefits may not be extensively documented, the overall principles are well-supported by soil science.

Alignment with FARM Program
FARM Environmental Stewardship (ES) V2-V3 Alignment
The optional FARM ES Conservation Practice Questionnaire (CPQ) also asks about compaction prevention.
Contents
We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights.
We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights.
Controlled traffic (CT) is the practice of operating farm machinery over the same paths in the field year after year. GPS technology is utilized to guide machinery precisely along these designated paths, ensuring consistent traffic lanes. As a result, compaction is confined to a small proportion of the field, typically less than 25% of the soil surface. By limiting machinery traffic to specific lanes, less of the field is impacted by equipment and compaction, and the most severe compaction is limited to a small area of the field.
Wide-scale adoption of CT has not yet occurred in the U.S., although it is likely moving in this direction with the increasing acceptance and implementation of guidance systems.
Practices and technologies
Compaction Prevention: Controlled Traffic
alternative practice name:
Controlled Traffic Farming; CTF; Tramlines; Skip Rows