A compactable driveway gravel or properly graded crushed aggregate is often a good choice, especially when installed over a stable base.
The required depth varies according to soil conditions, traffic, drainage, and equipment loads. Heavier agricultural traffic generally requires stronger base preparation.
Drainage is essential for long-term performance. Water that remains on or beneath the lane can contribute to erosion, rutting, and soft spots.
Yes, crushed concrete can be suitable for certain base and access-road applications when the material meets applicable requirements and is properly installed.
Usually, simply placing gravel over very soft or saturated soil is not the best long-term solution. The weak area may need grading, drainage improvements, stabilization, or additional base material first.