Use the Tracing tab to determine the size of the buffer displayed around trace results.
Select the Draw Buffer checkbox to turn on the buffer. If this checkbox is left unchecked, no buffer is displayed with the trace results. Enter a value in the Buffer Distance field to determine the size of the buffer. This field is displayed in the same units as the map (feet, in the example).
Drawing a buffer on a large number of edges can take an extended period of time. You may set a threshold at which a warning is displayed and you may choose not to draw the buffer. Enter this value in the Threshold field. This value may not exceed 10,000. If the number of elements exceeds 10,000, the buffer is not drawn.