While a long time coming, the latest update (March 1994) contains many new and powerful features. You should, of course, read the update "readme" available through menu selection 8 on the TMODEL2 Main Menu.

Major new capabilities include custom and LAN configurations, display of layer files in the network graphic editor and the travel/land use viewer, and HOV/SOV assignments.

You may now set TMODEL2 to operate from a specific project/data subdirectory so that the configuration in terms of network size and all other configuration choices may be specific to that project. The same is true of operating from different workstations on a LAN. See TMREADME.DOC for details. Keep in mind, however, that the single station license allows only one person at a time to use TMODEL2. If you have more than one person using any parts of TMODEL2 concurrently, you must have a license for each.

A layer file is simply a file of straight lines with a color attached to each line. Layer files may be displayed in the background in the network graphic editor and the travel/land use graphics viewer.

A layer may be a subset of TIGER files, displaying roadways over which you can digitize an appropriate transportation network; a TIGER file displaying census tracts, block groups, and blocks to help you better define and guild your traffic analysis zone system; a TAZ system developed elsewhere; background features (e.g., hydrographic features) which enable you to better visualize your network; or whatever you find helpful, providing it contains appropriate coordinate data. See menu item 4.4.9 in TMREADME.DOC.

The HOV/SOV Assignment module is now available as 3.13/14. It is designed to allow inclusion of modes which do not have access to all the links and/or nodes in the network. For example, a trip table full of low occupancy vehicles should not have access to HOV lanes. Or, certain classes of trucks may be restricted to specific routes, which is the same as being restricted from other routes.

TMODEL2 accomplishes this on a single, all-inclusive network by using a different input trip table for each mode (up to 3) and different node and/or link delay coefficients and turn penalties for each mode. To represent HOV lanes, two parallel links can connect a pair of nodes, each with its own attributes.

The results are stored in a loaded link file in which the volumes contain the assignments of all three modes (trip tables). SZ1 contains the assignments from the first mode, and SZ2 the assignments from the second mode. The third can, of course, be calculated from the others. Travel Time Matrices can be saved for each mode as well.

The HOV/SOV module is assignment only, i.e., you must develop the trip tables individually using 3.1) Gravity Module Distribution, 3.3) Full Featured Distribution/Assignment, or 2.6) Post Distribution Mode Split.

Other improvements include options to export turn volumes to the link file, merge turn movement files, compare and combine land use data files, factor and normalize land use, analyze trip length frequency distributions. Minor improvements have been made to every one of the 65 modules in TMODEL2. If you have anything special that you would like added, please give us a call.