Table 3.1.6.4 of the 1999 TAC Geometric Design Guide provides values for "shy line offsets". In the text regarding this table the TAC Guide states that "Roadside barriers should be placed beyond the shy line offset ..."
The problem I have is with a proposed guide rail installation on the left side (median side) of a divided highway. The typical cross section for this roadway shows a 1.5 m shoulder on the median side. Should having the face of the guide rail offset 1.5 m from the edge of the left lane be a concern when Table 3.1.6.4 gives a value of 3.2 metres?
The reason I ask is that the shoulder widths shown for various typical cross sections in the TAC guide also appear to conflict with the Table 3.1.6.4. Am I missing something or misunderstanding the use of table 3.1.6.4?
The problem I have is with a proposed guide rail installation on the left side (median side) of a divided highway. The typical cross section for this roadway shows a 1.5 m shoulder on the median side. Should having the face of the guide rail offset 1.5 m from the edge of the left lane be a concern when Table 3.1.6.4 gives a value of 3.2 metres?
The reason I ask is that the shoulder widths shown for various typical cross sections in the TAC guide also appear to conflict with the Table 3.1.6.4. Am I missing something or misunderstanding the use of table 3.1.6.4?
