In the Arterial LOS method, a segment is the basic unit of length which is defined as the “one-directional distance from one intersection to another”. It can include one or more links in TRAFFIX™, as cross-streets and two-way stop intersections may be located between the two signalized intersections.
Level of service is not calculated at the segment level.
If segments are not manually selected for a given Route, TRAFFIX™ automatically will select the link(s) between signalized intersections and/or all-ways stop intersections as segments.
If for some reason, the user defines a segment that has a signalized intersection between its ends, TRAFFIX™ will calculate the running time based on the average distance between the intersections and a weighted average of the free-flow speeds. An error message will be generated if the distances between two or more intersections differ by more than 20 percent, as specified in the HCM.