MSE walls can be built with a variation of soil reinforcement lengths vertically in one section. This is called a trapezoidal MSE wall section, and is outlined in the FHWA guidelines.

AASHTO 11.10.2.1 discusses shortening bottom strips to 0.4H minimum provided the wall is founded on rock or very competent foundation soil.

Among other design criteria in FHWA NHI-10-024 for trapezoidal MSE walls, geometrically the minimum base length (L3) is 0.4H or 8 feet, whichever is greater. The difference in length between each step or zone must be 0.15H or less.