If the arm is “in effect” an entry-only arm. You should measure the separation between the centres of the entry and the previous ENTRY (on a previous arm). If the separation is greater than 160 metres, 160 should be entered.
ALL arms of ‘large’ or grade-separated junctions should have a separation distance entered.
When you specify that “Grade Separated Entries passing over/under roundabout” the analysis program uses different capacity relationships from those used normally. They should also be used for large roundabouts (>130 metres). The relationships used are those defined in “The capacity of entries to very large roundabouts” (Marie Semmens, 1988).