Implementing the Concept of Reliability for Highway Capacity Analysis

2007 ◽  
Vol 2027 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Werner Brilon ◽  
Justin Geistefeldt ◽  
Hendrik Zurlinden
Keyword(s):  
Capacity Analysis ◽  
Highway Capacity

Variations in Capacity at Signalized Intersections with Different Area Types

2000 ◽  
Vol 1710 (1) ◽  
pp. 199-204 ◽  
Author(s):  
Xuewen Le ◽  
Jian Lu ◽  
Edward A. Mierzejewski ◽  
Yanhu Zhou
Keyword(s):  
Signalized Intersections ◽  
Capacity Analysis ◽  
Adjustment Factor ◽  
Highway Capacity ◽  
Left Turn ◽  
Highway Capacity Manual ◽  
Central Florida ◽  
Start Up ◽  
Study Results ◽  
Lost Time

The capacity analysis procedure for signalized intersections included in the Highway Capacity Manual (HCM) needs to consider the area type of a given intersection. The area-type adjustment factor used in the procedure is based on conclusions from a limited number of studies. In addition, the procedure for using an area-type adjustment factor is not well defined in the HCM. A study undertaken in central Florida to study the effects of four different area types on the capacity of signalized intersections is summarized. These four area types include recreational, business, residential, and shopping. Study results indicated that differences in saturation headways among different area types were significant. The saturation headways observed in recreational areas were significantly higher than those in other areas for both left-turn and through movements. The through-movement saturation headways obtained in residential, shopping, and business areas were not significantly different. This study resulted in a new area-type adjustment factor of 0.92 for recreational areas, whereas the factor is 1.00 for other areas. Results in this study also indicated that the differences in start-up lost time among different area types were not significantly different. In addition, according to the results of the analysis, 75 percent of the yellow interval in undersaturated conditions and 35 percent of the yellow interval in oversaturated conditions were found to be unused and considered clearance lost time.

Models for Right-Turn-on-Red and Their Effects on Intersection Delay

1997 ◽  
Vol 1572 (1) ◽  
pp. 131-139 ◽  
Author(s):  
Ghassan Abu-Lebdeh ◽  
Rahim F. Benekohal ◽  
Bashar Al-Omari
Keyword(s):  
Capacity Analysis ◽  
Highway Capacity ◽  
Average Delay ◽  
Highway Capacity Manual ◽  
Turn On ◽  
Significant Difference ◽  
Actual Field ◽  
The Difference ◽  
Exclusive Right ◽  
Delay Difference

Models to estimate right-turn-on-red (RTOR) volumes at intersections with exclusive right-turn (RT) lanes are developed, and the effects of RTOR volumes on computed delay are assessed. The important variables in these models are the RT volume, followed by green-time-to-cycle (G/C) ratio, volume of conflicting traffic, and whether there is a protected phase for opposing left-turning vehicles. The estimated RTOR increased as the RTs increased. However, it decreased as G/C and the volume of conflicting traffic increased. Results show that not accounting for RTOR volumes can lead to a significant difference in delay estimates for RT lanes and, to a lesser extent, on the corresponding approaches. For RT lanes, in one-half of the cases the difference was greater than 5 percent, in more than one-quarter of the cases the difference was greater than 10 percent, and in at least one of eight cases the difference was greater than 20 percent. Differences for individual cases ranged between 0 and 130 percent, with an average of 12 percent. For approaches, the average delay difference was 4 percent, and for individual cases the difference ranged between −2 and 78 percent. As recommended by the Highway Capacity Manual, actual field counts of RTOR volume should be used whenever available. However, in the absence of such counts, the models developed here can be used and hence should be considered in capacity analysis procedures.

Review and Evaluation of Methods for Analyzing Capacity at Signalized Intersections

1997 ◽  
Vol 1572 (1) ◽  
pp. 160-166 ◽  
Author(s):  
Catherine C. McGhee ◽  
Eugene D. Arnold
Keyword(s):  
Simulation Model ◽  
Traffic Engineering ◽  
Queue Length ◽  
Computer Programs ◽  
Signalized Intersections ◽  
Capacity Analysis ◽  
Highway Capacity ◽  
Operational Characteristics ◽  
Study Results ◽  
Departments Of Transportation

Capacity analysis is a critical activity in traffic engineering and planning divisions of state departments of transportation across the nation. The Highway Capacity Manual (HCM) provides a methodology for capacity analysis that is commonly accepted and often required by state departments of transportation. The variety of computer programs that exist to aid transportation professionals in conducting capacity analyses has led to questions regarding the best methods to use under various conditions. Several computer programs other than the Highway Capacity Software (HCS) that are commonly used in evaluating capacity at signalized intersections were evaluated to determine which ones provide acceptable results. The results obtained from a simulation model were also evaluated to determine whether the model could be used to determine the operational characteristics of signalized intersections. The study results, although based on limited data, provided valuable information about the programs evaluated. HCS, SIGNAL94, HCM/Cinema, and the simulation model TRAF-NETSIM are all acceptable for capacity analysis at isolated intersections. SIGNAL94, HCM/Cinema, and TRAF-NETSIM provide reasonable estimates of queue length at isolated intersections. However, at isolated intersections where congested, oversaturated conditions exist, TRAF-NETSIM provides more accurate measures of delay and queue length. At nonisolated intersections where queueing and spill-back are potential problems, simulation analysis with TRAF-NETSIM is recommended instead of capacity analysis to determine the operational characteristics of the corridor.

Implementing Auxiliary through Lanes in Context of Highway Capacity Analysis

2012 ◽  
Vol 2286 (1) ◽  
pp. 21-28
Author(s):  
Zachary Bugg ◽  
Nagui M. Rouphail ◽  
Bastian J. Schroeder ◽  
Brandon Nevers
Keyword(s):  
Capacity Analysis ◽  
Highway Capacity ◽  
Auxiliary Through Lanes

scholarly journals Multi Vehicle-Type Right Turning Gap-Acceptance and Capacity Analysis at Uncontrolled Urban Intersections

2018 ◽  
Vol 48 (2) ◽  
pp. 99-108 ◽  
Author(s):  
Doddapaneni Abhigna ◽  
Dipak P. Brahmankar ◽  
Kodavanti Venkata Raghavendra Ravishankar
Keyword(s):  
Capacity Analysis ◽  
Vehicular Traffic ◽  
Gap Acceptance ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Vehicle Type ◽  
Traffic Stream ◽  
Critical Zones ◽  
The Right

Intersections are the critical zones where conflicting, merging and diverging movements influence the intersection capacity. Uncontrolled intersections in particular pose dangerous situations to vehicular traffic. During peak vehicular flow, the unpredictable crossing behavior of minor stream vehicles induces delay and reduces the capacity of the intersection. Capacity at uncontrolled intersections is typically measured either by gap acceptance method, empirical regression approaches and conflict technique. Gap acceptance is an important characteristic for analyzing uncontrolled intersections. The behavior of different vehicle types and gap of subject vehicle type from minor street taking right turn to merge with major traffic stream is analyzed using gap acceptance method. The objective of the current study is to analyze the effect of major stream vehicle type combinations on the minor stream vehicle gap-acceptance behavior and to determine the capacity of the minor stream taking into account the influence of the right turning vehicles. The capacity of minor stream calculated using Highway Capacity Manual (HCM) 2010, Luttenin’s model, and Tanner’s model are compared. It is observed that two wheelers are more aggressive than three wheelers for most of the major stream vehicular combinations observed in this study.

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