Path control measures to reduce traffic noise impacts include roadway alignment, site planning, noise barriers, and building insulation. Roadway alignment and site planning are most effective when included during the project planning stages. For existing noise problems, roadside noise barriers are effective, providing reductions of up to 15 dB(A). Some sites require building insulation to reduce traffic noise impacts. Three levels of modifications are considered: (1) sealing leaks, (2) modification of small structure elements, and (3) wall panel modifications.