SR 05:070 - Laserfiche WebLink

questions and to bring all Councilmembers/Commissioners up to speed on what these descriptors mean. Much of this information was included in the "Annual Baseline Traffic Report- 2003." The relevant tables - slightly revised/updated - are reproduced in this report for ease of reference. More detailed background information, however, may be found in the "Baseline Report." LEVELS-OF-SERVICE DESCRIPTORS Intersection operational conditions are described as a "level-of-service" (LOS), graded from LOS A (free-flowing) to LOS F (very congested). The conditions are expressed as average delay, calculated by utilizing the 2000 Highway Capacity Manual methodology. The descriptions for each LOS category are listed in "Exhibit 1 - HCM Level of Service (LOS) Descriptions," attached. Attached to this report is Appendix A - Explanation of Level-of-Service Concept. This is a summary ora Synchro/Sim Traffic presentation which staff will present at the workshop. This presentation will show actual traffic moving through the simple intersection at various levels-of-service and should provide the Council, Commission, and public with an understanding of what these descriptors mean in the real world. Roadways operate at various levels-of-service based on traffic volume, just as intersections do. Exhibit 1 includes descriptors of roadway levels-of-service. For City streets, the capacity constraint is almost always intersection capacity, not street capacity, and, thus, City street levels-of-service are not included in this report. For freeways, however, the roadway level-of-service descriptor is appropriate. Several additional facts should be remembered when reviewing the Levels-of-Service tables. The LOS calculation is based on the peak traffic during 15 minutes within the two-hour AM (7:00 a.m. - 9:00 a.m.) and PM (4:00 p.m. - 6:00 p.m.) periods. For intersections with LOS A-C, it is likely that the LOS perceived in the other 45 minutes of the peak hour (or one hour, forty-five minutes of the peak two-hour period) is better. However, as intersections reach LOS D-F, the congested period is typically longer. Exceptions, however, occur at certain school-impacted intersections where the peak period may be short, even if at LOS D~F. The LOS descriptor is a measure of"average delay" of all vehicles at the intersection. Certain legs of an intersection, or certain movements, may experience more delay than others. The tables show overall intersection delay as well as delay at each leg, but not at each movement (left-turn, through, right-turn movements). SR 05:070 Page 2