I. INTRODUCTION
Highway Capacity Manual 2000
In this chapter, a brief overview of the analytical procedures in this manual, their
organization into chapters, and guidance on their general application are provided.
The analytical procedures in this manual can be used for a number of applications
covering a broad range of facility types. The facility types are distributed among five
categories: urban streets, pedestrian and bicycle facilities, highways, freeways, and
transit.
In Chapters 10 through 14, for each of the five categories, general concepts are
presented, required inputs for each methodology are identified, reasonable
approximations for specific parameters are suggested for use if local data are not
available, and example service volume tables are provided. The Part II chapters also
contain special procedures used to supplement the planning applications defined in the
Part III chapters.
II. OVERVIEW OF ANALYTICAL PROCEDURES
For the analytical methods defined in Part III, the calculations of average speed,
density, and delay will provide insight into the level of service for what is considered a
steady-state condition. This means that the outputs provided by the computational我不曾爱过你 我自己骗自己
methods are considered representative for the length or area of the analysis and for the
generally not appropriate (unless the analyst performs a special intervention) for the
evaluation of inclement weather conditions, accidents or construction activities, queues
that are building over both time and space, or the possible effects of vehicle guidance or
driver guidance systems typical of intelligent transportation systems. However, some
guidelines are identified in Chapter 22 to address these conditions.
The Part III methods have been designed to be sensitive to roadway, traffic, and
control characteristics of the facility. However, the methods cannot predict the effects of
changes in the posted speed limit, the level of police enforcement, safety features, driver
education, or vehicle performance.
subsystems located in a defined study area or corridor. The six subsystems are freeway,
urban street, rural highway, transit, pedestrian, and bicycle. Each transportation
subsystem is composed of two or more individual facilities. The facilities within each
subsystem are all of a single type (freeway, urban street, rural highway) or mode (transit,
pedestrian, bicycle). Each facility is in turn made up of segments and points. For
example, a freeway contains basic, weaving, and ramp merge/diverge segments. An
urban street contains street segments and intersections (points).
刘特家里是做什么的A segment is a length of facility where demand and capacity are relatively constant.
Each segment begins and ends at a point. Segments are generally directional; for
example, each stretch of two-way street is composed of two one-way segments. The
exception to this is two-lane highways, where each segment is bidirectional but can be
split into two directional segments for analysis. A point is a very short length of facility
where demand or capacity changes abruptly from conditions on the upstream or
downstream segment.
Analysis of the transportation system proceeds from estimates of travel times and
当秀发拂过我的钢delays at the segment and point levels using the methods described in Part III. Segment
and point delays and travel times are converted to total person hours of delay or travel
time and then summed to obtain facility estimates.
Chapters 10–14 of Part II
present general concepts
Part III, Chapters 15–27,
presents methodologies
A facility is composed of
segments and points
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9-1
Chapter 9 - Analytical Procedures Overview
Introduction
Highway Capacity Manual 2000
Part IV, Chapters 28–30,
presents corridor and
areawide analyses
Part V contains
information on simulation
and other models
For analyses that combine facility types or that address a corridor or expanded area,
the analyst must consult Part IV. Part V contains useful information on applications of
simulation and other models to complement the use of HCM 2000 methodologies.
Exhibit 9-1 illustrates the content, by chapter, of the analytical sections of this
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