Cover Image

Not for Sale



View/Hide Left Panel
Click for next page ( 97


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 96
96 CHAPTER 10 Accomplishment of Research Objectives Exhibit 101 illustrates how the recommended modeling system meets the research objectives.

OCR for page 96
97 Exhibit 101. Satisfaction of Research Objectives by the Recommended Modeling System. Research Objective Degree Accomplished By Proposed Model System 1. Produce updated chapter on multimodal LOS Draft chapter, sample problems, and software analysis for urban streets for Highway Capacity engine delivered to panel in June 2007 and to Manual. Produce sample problems. Produce Highway Capacity Committee in July 2007. Final software engine. Report delivered February 2008. 2. Establish a scientific basis for evaluating level The research has established a measurable of service as a function of traveler satisfaction. definition of level of service and a reproducible method for measuring it. The model system is based on video labs and field surveys conducted in several cities in the United States. 3. Create a consistent set of modal LOS models The uniform definition of LOS used in the models allowing for comparison of degrees of modal provides a consistent basis for comparing levels of traveler satisfaction across of modes. service across modes. 4. Provide a multimodal LOS system that takes The multimodal LOS system takes into account the into account interactions among modes in the impacts of autos, buses, bicycles, and pedestrians urban street environment. on the perceived LOS for each mode. Many cross- modal factors are taken into account directly, others are incorporated indirectly. Explicit numerical methodologies do not yet exist for incorporating the indirect effects into the LOS models, but the "hooks" are in place in the LOS models for future incorporation of new methods for estimating the indirect effects. 5. Create a multimodal LOS system that is The LOS system is applicable to arterials and applicable to arterials and major collectors major collectors. 6. Create a multimodal LOS system that The multimodal LOS system concept allows the addresses all vehicle and pedestrian movements. consideration of all movements by vehicles and pedestrians. The LOS models themselves have been implemented primarily for through travel along the arterial or collector. The pedestrian model, in addition, incorporates mid-block crossing. 7. Create a multimodal LOS system that can be The LOS system can be applied to peaks shorter used to evaluate micro-peaks (less than 15 than 15 minutes; however, the models that minutes). implement that system are designed for 15 minute peaks. 8. Incorporate safety and economic aspects only Safety and economic effects have not been insofar as they influence perceptions of LOS. explicitly included or excluded from the LOS models. Laboratory and field survey participants were allowed to consider any aspect of the service provided in determining their perceived levels of service. 9. Overcome the nine limitation of the HCM listed a. The presence or lack of parking is included in in Chapter 15 of the HCM. the bicycle and pedestrian LOS models. It indirectly affects the auto and transit LOS models. b. Driveway density and access control is included in the bicycle LOS model. c. Short lane additions and drops are not explicitly included in any of the LOS models. d. The impacts of road gradients are not included in the currently proposed LOS models, but could be added. e. Capacity constraints between intersections are taken into account to the extent they affect stops by autos or delay bus service. f. Two-way left turn lanes and medians are not explicitly included in the LOS models but can indirectly affect auto and bus LOS by reducing stops, or increasing bus speeds. g. High percentage turning movements explicitly affect pedestrian LOS. They indirectly affect auto and bus LOS. h. Multi-block queues will cause problems for the auto LOS model, which considers only stops. Under the recommended model, a single stop for a long queue gives better auto LOS than multiple stops for several short queues. i. Cross street congestion blocking through traffic will indirectly affect auto and bus LOS and will directly impact pedestrian LOS.