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Appendix F: Level of Service (LOS) <br />Research Brief — Volume No. 3 <br />LOS A <br />LOS C <br />LOS D = Acceptable <br />LOS F = Unacceptable <br />Source: City of San Jose, CA. <br />Although a Level of Service <br />rating of A represents the best <br />traffic operations, it is not always <br />the most desirable. Providing <br />LOS A for all corridors and all <br />operations at all times would <br />require a significant amount of <br />land to be devoted to the road <br />infrastructure, which makes it <br />extremely costly to build and <br />maintain. During non -peak <br />times, like overnight, much of <br />that infrastructure would sit <br />unused. <br />On the opposite side of the <br />spectrum, a Level of Service <br />rating of E and F represent traffic <br />operations close to breaking <br />down, or that already have. <br />These ratings mean high delays, <br />long queues, and slow speeds, <br />not to mention driver frustration. <br />Instead of trying to achieve <br />one or the other, government <br />agencies try to strike a balance <br />between providing acceptable <br />operations, neither falling nor <br />flowing too freely. Because <br />of this, LOS D is typically <br />considered the lowest LOS <br />acceptable by government <br />agencies and is reflective of a <br />balanced approach between <br />cost and benefit. <br />There are many tools and guidelines used to determine a <br />roads Level of Service rating. Simple tools like generalized <br />roadway capacities allow for planning -level efforts. While <br />inexpensive and quick to complete, they are not as accurate <br />as other options. More complicated tools, such as mi- <br />cro -simulations, provide more accurate results, but cost <br />more and take more time. It is important to understand the <br />trade-offs between the analysis types as well as the purpose <br />of the study. <br />Potential Accuracy <br />Detail e dAnalysis <br />Signal Timing, Corridor Evaluation <br />(Micro Scopi c An alysis) <br />Operational Analysis <br />Intersection Needs, Geometric Decisions <br />(Macro-Scopic Ana ysis) <br />Prelim nary Engineering <br />ROW Needs Cost Estimates <br />(Spreadsheet/Formula Analysis) <br />Aigr <br />Planning Level <br />LongTerm Plans, ROW Needs <br />(Generalized L45Table s) <br />Effort/Complexity 11110 <br />Source: Florida Deptarment of Transportation <br />Resources <br />• Highway Capacity Manual, fifth edition <br />• Nation Cooperative Highway Research Program Report 616; <br />Multimodal Level of Service Analysis for Urban Streets <br />• http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp rpt 616. <br />pdf <br />• Florida Department of Transportation Quality/Level of Service <br />Handbook <br />• http://www.dot.state.fl.us/planning/systems/programs/sm/ <br />los/pdfs/2009FDOTQLOS Hand book.pdf <br />About This Brief <br />Spack Consulting prepared this brief as part of our company's vision to significantly improve the practice of traffic engineering <br />and transportation planning. Transportation professionals from around the world have assisted us in developing this <br />document. We are providing this brief under the Creative Commons Attribution License. Feel free to use -modify -share this <br />guide, but please give us some credit in your document. To request our whole series of Design Briefs and to be included <br />on our distribution list for new materials, please email mspack@spackconsulting.com. And please reach out if you have <br />any comments or questions related to this Design Brief. <br />MikeOn <br />traffic <br />5 PACK COUNTING <br />ccirs.com <br />ACADEMY <br />F2 <br />=■ <br />Y <br />TRAFFIC DATA INC. <br />Spack Consulting <br />_CONSULTING <br />rams impact Study Pearson Farm Residential Development <br />