Airport Curbside and Terminal Area Roadway Operations (2010) / Chapter Skim
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Pages 30-40
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From page 30... ...
Chapter 5 presents comparable methods for analyzing curbside roadways. As described earlier, a hierarchy of analytical methods -- including quick-estimation, macroscopic, and microsimulation methods for analyzing airport terminal area roadway and weaving section operations, is proposed.
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From page 31... ...
a high proportion of drivers who are infrequent users of, and are, therefore, unfamiliar with, the airport roadways. The free-flow speeds can be approximated by the posted speed limits on the roadway section unless drivers Level of service Criteria A B C D E Free-flow speed = 50 mph Minimum speed (mph)
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From page 32... ...
These service volumes were developed using the macroscopic method described in the next section. Macroscopic Method for Analyzing Airport Roadway Weaving Areas The 2000 HCM and the draft 2010 HCM provide methodologies for evaluating traffic operations on airport roadways.
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From page 33... ...
Second, special LOS threshold traffic densities were developed for application to weaving sections on low-speed airport roadways. As an input in determining the capacity of the weaving segment, maximum service flow rates for basic freeway segments under base conditions were extrapolated to correspond to input free-flow speeds (i.e., less than 55 mph)
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From page 34... ...
Determine Weaving Configuration Several key parameters characterize the configuration of a weaving segment. The first step is to determine whether the roadway being analyzed is a one-sided ramp weave or a twosided weave (illustrations are provided in QATAR as well as in Figures 4-1 and 4-2)
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From page 35... ...
For a two-sided weaving segment, only the ramp-to-ramp movement is functionally "weaving." The following values are established: LCRR = minimum number of lane changes that must be made by one ramp-to-ramp vehicle to successfully execute the desired maneuver. LCMIN = LCRR vRR vRR = ramp-to-ramp demand flow rate in weaving segment, pc/hr.
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From page 36... ...
, draft 2010 HCM, c c N f fW IWL HV P= Chapter 11, Exhibit 11-17, and interpolated for lowspeed airport access roadways. Weaving segment capacity determined by weaving demand flows.
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From page 37... ...
SMIN = minimum average speed of weaving vehicles expected in a weaving segment, miles/hour; the recommended setting for low-speed airport roadways is 10 miles/hour. SMAX = maximum average speed of weaving vehicles expected in a weaving segment, miles/hour; the recommended setting for airport roadways is the posted speed limit (unless a speed survey or field observations by the analyst indicate that a different speed is appropriate)
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From page 38... ...
Under the above conditions, microsimulation models may be more appropriate for evaluating traffic operations. 38 Level of service Freeway weaving segments (pc/mi/ln)
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From page 39... ...
Each "vehicle" then travels through a computerized roadway network, and various aspects of its performance are recorded during its simulated trip based on its interactions with other vehicles and traffic controls. These performance statistics can be summarized in many ways, including performance measures commonly used by traffic engineers and transportation planners (e.g., delays, travel times, travel speeds, and queue lengths)
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From page 40... ...
with the travel times resulting from different levels of traffic demand and access and circulation roadway configurations. However, it is difficult to accurately estimate these travel times and queues without the aid of microsimulation models because of the relative short distances being analyzed and the difficulty in estimating queue lengths through other means.
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