How do I set the lane geometry and sign codes for an approach from the stem of a “T” intersection?
Version 7 of QRS II behaves somewhat differently than earlier versions. In earlier versions of QRS II, the lane geometry and sign code was ignored for traffic coming from the stem of the T. The reason for this was that QRS II could not detect the existence “left” turns anyway and there could be at most one exclusive right lane. The capacity of the approach was dictated by the through lanes only. In version 7, QRS II tries to use the approach codes, if possible. Again, with no opposing traffic, left turns will be treated as “other” movements and lumped in with throughs. Right turning lanes, however, will add capacity. For example, an approach from the stem of a T with one true left and one right lane should be coded as having a single through lane (capacity of about 1800 vphg) and one right lane. In some instances it may be desirable for left turning lanes to be explicitly shown. For these lanes to have any effect, the network must suggest the possibility of opposing traffic by having a
