Improved Analysis of Two-Lane Highway Capacity and Operational Performance

Washburn, Scott S; Al-Kaisy, Ahmed; Luttinen, Tapio; Dowling, Richard; Watson, Donald C.; Jafari, Alireza; Bian, Zilin; Elias, Aaron

doi:10.17226/25179

Cited by 12 publications

(12 citation statements)

References 24 publications

(71 reference statements)

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“…However, measuring the value of PTSF is impractical in real traffic conditions [6] and, for this reason, HCM itself recommends the use of a surrogate measure called percent followers (PF). The PF indicator is essentially defined as the percentage of vehicles in traffic flow traveling with a follower time headway of less than or equal to 3 s.…”

Section: Literary Reviewmentioning

confidence: 99%

“…On the other hand, research in this field is up to date, and it is always trying to test HCM methodologies with respect to actual traffic conditions and driver behavior, which may vary from country to country [24,25]. Washburn et al [6] recently defined a new methodology, based on the estimation of the free flow speed (FFS), ATS, and PF. For the PF estimate, an exponential-type function is used with slope and power coefficients obtained by applying a chain of parametric equations, depending on the length of the segment, the FFS, and the percentage of heavy vehicles moving in the opposite direction.…”

Section: Literary Reviewmentioning

confidence: 99%

“…A deterministic threshold approach for time headways between vehicle pairs has been widely used in numerous studies, as a cut-off between free and non-free moving behavior, as summarized in recent reviews [4][5][6], with values that, in most cases, are around the 3 s threshold value. This 3 s value is the headway threshold proposed by the HCM [7] to distinguish non-follower and follower vehicles; in other words, vehicles that are free to actuate their desired speeds or not, due to slow vehicles.…”

Section: Introductionmentioning

confidence: 99%

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A Statistically Based Model for the Characterization of Vehicle Interactions and Vehicle Platoons Formation on Two-Lane Roads

Mauro

Pompigna

2022

Sustainability

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Two-lane roads are the most significant part of the road network in many countries, and are widely used for systematic and non-systematic daily travels. Traffic on a two-lane road typically involves a high level of interaction among vehicles, with the formation of platoons. As a part of the road network of a country, they represent a crucial development factor from a social and economic point of view, because they ensure the close accessibility of the innermost areas and local markets, and favor the connection between the nodal points of the logistic system and the last mile of the supply and distribution chain. Thus, the estimation of the presence of vehicle platoons makes it possible to develop significant indicators for performance analysis on this type of road, which in turn is the basis for planning, upgrading, and improving transport programs to find a sustainable balance between environmental, social, and economic qualities. This paper presents a statistically based model, the Two-Lane Roads Statistical Platooning Model (TLR-SPM), which allows for evaluating the percentage of vehicles which are free to travel at the desired speed and of non-free vehicles constrained to travel in platoons at lower speeds than desired, as a function of the traffic flow. Based on a data-driven methodological approach, TLR-SPM allows for going beyond the critical threshold value for time headways, such as the widespread 3 s threshold, but lacks the need to hypothesize, identify, or estimate the probability laws for speed and time headway. From the formal treatment of the general statistical method, the paper shows the data processing procedure through its application to a real case. As shown by the application case and the comparisons with the results of other methods, the proposed model can significantly adapt to the experimental data and can support in analyzing a two-lane road in its operating conditions to promote its safety and efficiency as part of a sustainable transport system.

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Section: Literary Reviewmentioning

confidence: 99%

Section: Literary Reviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Statistically Based Model for the Characterization of Vehicle Interactions and Vehicle Platoons Formation on Two-Lane Roads

Mauro

Pompigna

2022

Sustainability

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“…This is a simplification of PTSF, which is extremely challenging to observe, and could be considered a practical method. However, it is thought that use of a single threshold to determine followers in this manner does not give adequate consideration to the randomness of driver preferences or to travel speed and vehicle type ( 4 , 5 ). For example, different drivers may feel that they are following other vehicles at different headways, and PTSF may differ even with the same headway because of factors such as travel speed and vehicle length.…”

Section: Qos Performance Measure For This Studymentioning

confidence: 99%

Methodology to Evaluate the Quality of Service of Traffic Flow on Intercity Expressway Sections by using Follower Percentage

Konda¹,

Nakamura

2020

Transportation Research Record

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This study estimated composite headway distributions consisting of follower and non-follower headway elements and used the follower percentage obtained as the estimated parameters of those distributions to evaluate the quality of service (QOS) of traffic flow on Japanese intercity expressways under uncongested conditions. Analysis of pulse data obtained by vehicle detectors at multiple points with differing geometric structures showed that follower percentage is influenced by lane traffic volume, vehicle pair, and lane operation. Use of follower percentage also enabled clear and quantitative comparison and evaluation of the QOS of traffic flow for different lane operation formats, which could not be adequately expressed by such conventional macroscopic indices as average speed and traffic density. This indicates that follower percentage is a suitable performance measure for evaluating the QOS of traffic flow.

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“…is is especially relevant to calculate percent followers. Currently, the threshold to determine the following conditions is 3.0 seconds [61], but other studies suggest that this value should be between 2.5 and 2.6 seconds [62,63]. is fact is even more relevant in safety analyses because most of the traffic microsimulation tools do not account for traffic conflicts, such as time-to-collision.…”

Section: More Flexible Complex and More Intense Modelingmentioning

confidence: 99%

2 + 1 Highways: Overview and Future Directions

Romana

Martin-Gasulla

Moreno

2018

Advances in Civil Engineering

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Most of the rural transportation system is composed of two-lane highways, and many of them serve as the primary means for rural access to urban areas and freeways. In some highways, traffic volumes can be not high enough to justify a four-lane highway but higher than can be served by isolated passing lanes, or can present high number of head-on collisions. In those conditions, 2 + 1 highways are potentially applicable. This type of highway is used to provide high-performance highways as intermediate solution between the common two-lane highway and the freeway. Successful experiences reported in Germany, Sweden, Finland, Poland, or Texas (US) may suggest that they are potentially applicable in other countries. The objective of this white paper is to provide an overview of the past practice in 2 + 1 highways and discuss the research directions and challenges in this field, specially focusing on, but not limited to, operational research in association with the activities of the Subcommittee on Two-Lane Highways (AHB40 2.2) of the Transportation Research Board. The significance of this paper is twofold: (1) it provides wider coverage of past 2 + 1 highways design and evaluation, and (2) it discusses future directions of this field.

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Improved Analysis of Two-Lane Highway Capacity and Operational Performance

Cited by 12 publications

References 24 publications

A Statistically Based Model for the Characterization of Vehicle Interactions and Vehicle Platoons Formation on Two-Lane Roads

A Statistically Based Model for the Characterization of Vehicle Interactions and Vehicle Platoons Formation on Two-Lane Roads

Methodology to Evaluate the Quality of Service of Traffic Flow on Intercity Expressway Sections by using Follower Percentage

2 + 1 Highways: Overview and Future Directions

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