Stability of Freeway Bottleneck Flow Phenomena

Öğüt, Kemal Selçuk; Banks, James H

doi:10.3141/1934-11

Cited by 5 publications

(2 citation statements)

References 7 publications

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“…In such cases, it is often difficult to tell how many bottlenecks there are and which one is critical under given flow conditions. One such complex bottleneck was previously described by Öǧ üt and Banks (1). In that study, the sequences in which initial speed drops occurred at different locations in each of several extended freeway segments were noted for each of 44 days.…”

Section: Evaluation Of N-curve Methodology For Analysis Of Complex Bottlenecksmentioning

confidence: 78%

Evaluation of N-Curve Methodology for Analysis of Complex Bottlenecks

Kurada¹,

Öğüt

Banks

2007

Transportation Research Record: Journal of the Transportation R

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A complex bottleneck is a section that has several bottlenecks with varying patterns of activation in close proximity to one another; issues of concern are the number and location of individual bottlenecks and the events associated with their activation. The usefulness of N-curve methodology for analyzing complex freeway bottlenecks was evaluated by applying it in the reanalysis of a section of southbound I-5 near San Diego, California, that had been used in a previous study. The reanalysis was based on ordinary loop detector data and considered the relationship between changes in vehicular storage in individual sections (determined by N-curve analysis) and the time series of speeds. Information provided by the N-curve analysis contributed to improved understanding of the section by establishing the existence of multiple bottlenecks in two of the sections, but its contribution was modest when compared with what had already been learned from a careful analysis of speeds. A major difficulty in applying the N-curve technique was the uncertainty of the correction of accumulated errors resulting from count biases. A simple uniform correction proved inadequate in several cases because the biases appeared to be time-dependent; other approaches to bias correction led to plausible results in some of these cases but not others, and in all cases the uncertainty of the bias corrections leads to considerable uncertainty in the queue-size estimates.

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Section: Evaluation Of N-curve Methodology For Analysis Of Complex Bottlenecksmentioning

confidence: 78%

Evaluation of N-Curve Methodology for Analysis of Complex Bottlenecks

Kurada¹,

Öğüt

Banks

2007

Transportation Research Record: Journal of the Transportation R

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“…The analyses were conducted on the Trans European Motorway (TEM), which is the crucial main urban motorway in Istanbul, based on 15-min aggregated traffic flow characteristics. To accomplish this study, time-speed and rescaled cumulative flow rate graphs are used in order to determine the discharge flows precisely as mentioned in the literature [11,12].…”

Section: Introductionmentioning

confidence: 99%

Discharge Flow Rate Change Under Rainy Conditions on Urban Motorways

Aksoy

Öğüt

2018

PROMET

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Queue discharge flow is the most frequently observed phenomenon on urban motorways when demand exceeds capacity. Once a queue is formed, congestion arises, and the number of vehicles that can pass from downstream reduces. This reduction phenomenon is defined as the capacity drop and calculated by taking the difference between capacity and discharge flow at a road section. Obviously, this capacity drop exists after an onset of congestion and may increase in relation to weather conditions, such as rain, snow, or fog, which cause longer queues and delays. In this paper, the effect of rain on discharge flows is investigated and compared with sunny days on Istanbul urban motorways. Besides, rain precipitation during congestion is considered and related to discharge flow. Four different motorway sections were analyzed, and up to 37% discharge flow reduction was determined between sunny and rainy conditions. Motorway sections with higher free flow speed (FFS) were found to be more affected by rain, and discharge flow reduction was bigger compared to the section with the lowest FFS. For 1 mm/m2/h of precipitation, the discharge flow is estimated as 1,719 pcu/h/lane when FFS is 84 km/h, and as 1,560 pcu/h/lane if FFS is 104 km/h.

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Extended Bottlenecks, the Fundamental Relationship, and Capacity Drop on Freeways

Coifman¹,

Kim²

2011

Procedia - Social and Behavioral Sciences

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Stability of Freeway Bottleneck Flow Phenomena

Cited by 5 publications

References 7 publications

Evaluation of N-Curve Methodology for Analysis of Complex Bottlenecks

Evaluation of N-Curve Methodology for Analysis of Complex Bottlenecks

Discharge Flow Rate Change Under Rainy Conditions on Urban Motorways

Extended Bottlenecks, the Fundamental Relationship, and Capacity Drop on Freeways

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