3-Legged Intersections
TIAH V4 and later support 3-legged intersections. TIAH 4 is distributed with at least one “T” intersection and one 3-legged roundabout intersection blocks, and arrows for each block (note that users can create their own intersection blocks for use with TIAH).
Important Note: The 3-legged intersection feature can only be used after a standard run of TIAH Intvol insertions, that is, the drawing must already contain intersection blocks.
Because of the number of different data formats that TIAH supports and the number of variations in those file types, TIAH must make certain assumptions when reading the data. One of those assumptions is that if data is missing, then TIAH replaces any missing data with a 0 (zero).
There is no way to tell from reading the files if data is merely missing or if data is mistakenly omitted, or if the intersection is a 3 legged intersection. Thus, the initial run of intersection block insertions must always be with a 4-legged intersection block (default). The 3-legged intersection function replaces one or more user-selected 4-legged intersections already existing within the layout with 3-legged intersections of the desired type.
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After the initial TIAH run is complete, start the 3-legged intersection function by selecting “Intersection Switch” from the TIAH drop-down menu. Click here for more information. How to Customize To develop your own 3-legged intersection blocks or to modify an exiting block, please refer to the Help Sections on T-intersections and 3-Legged Roundabouts. Important Note: intersection volume blocks for T-intersections, 3- and 4-legged roundabout should be placed in the C:\Program Files\TIAH\INTVOL\3LEG directory. Similarly, arrows for these types of intersections should be placed in the C:\Program Files\TIAH\ARROWS\3LEG directory for the TIAH program to "see" them as available. |