Network Setup

Two-Lane Highway

Main Input Screen The main input screen (See Figures below) is where the roadway geometry is specified. This is done by adding segments/links where you can set the length, initial angle, free-flow speed, grade, and so on. Click ‘Add New Link’ to add a new roadway segment, click ‘Insert New Link’ to add a new roadway segment above the current segment you have selected, click ‘Delete Link’ to delete the currently selected segment.

Segment Input Fields Links and their corresponding characteristics are specified for the west-to-east or north-to-south travel direction (considered ‘Direction 1’) and the inputs for the opposing travel direction (considered ‘Direction 2’) are automatically created by the program.

Upstream/Downstream Node ID Each two-lane highway segment has a beginning and ending node. The upstream and downstream node Id identifies the segments before and after the currently selected segment. The node Id values are automatically created. Note that link Id values are created by concatenating the upstream and downstream node values. For example, Link Id ‘12’ corresponds to the link that has upstream node Id ‘1’ and downstream node Id ‘2’. Link Id ‘21’ corresponds to the link that has upstream node Id ‘2’ and downstream node Id ‘1’. For the two-lane highway module, link 21 would be created automatically by the program, as the opposing direction to link 12.

X Coord Start/X Coord End and Y Coord Start/Y Coord End The starting and end coordinates for each segment. These values are automatically created, based on the length and orientation angle, and horizontal curve inputs.

Length For tangent segments, the link length is entered in this cell. For curved links, the link length will be based on the curve radius and central angle. Consequently, the length cell for a curved link will be colored gray, indicating that it cannot be edited directly. User input of length is restricted to integer values; however, the program may replace entered values with decimal values as a consequence of curved links and/or coordinate point adjustments.

Orientation Angle This input corresponds to a compass angle based on the direction of travel (see Figure below).