There is a large number of types of two-stage crossings on urban and rural roads. The following two criteria can be used in choosing the Site Template or Network Template suitable for a particular two-stage crossing case:
Is there a median refuge (storage) space for Minor Road movements to slow down or stop in order to give way / yield to opposing movements in the second stage of manoeuvre?
Do the Minor Road movements give way / yield to Major Road Turns in the first or second stage of the manoeuvre (Major Road Turn is opposing in Stage 1 or Stage 2)?
The following Two-Stage Crossings at Unsignalised Intersections without median refuge are available as Site Templates according to the treatment of the Minor Road turn on exit:
Two-Stage T-Intersection (Added Lane)
Two-Stage T-Intersection (Priority Merge)
Two-Stage T-Intersection (Zipper Merge)
Two-Stage Crossing at Unsignalised Intersections with median refuge are modelled as a Network comprised of two closely-spaced Sites. The following Network Templates are available:
Two-Stage T-Intersection (Type A where Major Road Turn is Opposing in Stage 2 and Type B where Major Road Turn is Opposing in Stage 1),
Four-Way Intersection Two-Stage Crossing where Major Road Turns are Opposing in Stage 1, and
Wide-Median Unsignalised Intersection where Major Road Turns are Opposing in Stage 2.
Detailed information on modelling Two-Stage Crossings at Unsignalised Intersections can be found in SIDRA INTERSECTION 9.1 User Guide, Section 9.4.5. General information on Site and Network Templates is given in Section 2.3.