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Appendix F: Level of Service (LOS) EM CONSULTING Research Brief — Volume No. 3 Level of Service (LOS) 'qr 7 �� . J& Level of Service(LOS)is a qualitative description, similar to typical school grades, that traffic engineers use to communi- cate how good or bad traffic operations are on a corridor, intersection, or interchange. Common Factors Traffic can be a hard thing to quantify as everyone has a Level of Service criteria have been developed for multiple different tolerance for congestion. What seems excessively types of traffic operations including: long to one person may seem good enough for another. . Intersections These differences are readily apparent when comparing small towns or rural areas, where five cars an hour can • Urban Corridors be the norm, to big cities or downtowns, where less than • Freeways hundred cars an hour, even in the middle of night, is rare. . Transit Service • Bicycle Operations To combat this issue and provide a consistent measuring . Pedestrian Operations tool for traffic studies, a "Level of Service" rating was developed. Level of Service ratings are based on the roadway or intersection characteristics and the amount of The most common LOS criteria used is for car operations traffic. Just like grade school, LOS A represents the best at intersections; both signalized and unsignalized. For an traffic operations, where traffic flows freely. LOS F, on the intersection Level of Service analysis, average delay for other hand, represents failing operations, where the road cars travelling through the intersection is used to determine or intersection is congested and running beyond maximum the appropriate grade. A high delay results in a poor LOS capacity. LOS E is typically considered "at capacity" which rating and equates to poor operations. Similarly, low delay means the amount of traffic is right at the level the roadway results in a good LOS rating and equates to good or great or intersection can adequately accommodate. Using Level operations. of Service letter grades provides an easy way to convey LOS can be determined for the intersection as a whole, or road operations to the general public and has been adopted for individual movements. It is common during peak periods across the United States. in major population areas for an intersection to have an acceptable overall LOS rating, but fail to achieve a good grade for individual movements. Common Factors Impacting Level of Service •Number of Lanes. �+ - •Traffic Volumes. •Intersection Control (stop sign, signal, roundabout, a° interchange.) •Amount of access on a corridor. 60 •Percentage of turning traffic. 50 •Traffic signal cycle length (green time devoted to each 10 lG5 P approach) and phasing (one green for all approach movements or separate green arrows.) °° LOS •Percentage of heavy trucks. 20 LOS •Roadway Grades. 113 •Distribution of traffic within a peak hour as well as over the 0 course of a day. 1IRR5P1 wcItr0Enn RS,I$efsd�tl0d •Pedestrian activity. •Bicycle activity. Traffic Impact Study Pearson Farm Residential Development F1 Spack Consulting