Measurement of free-flow conditions on multilane intercity highways under heterogeneous traffic conditions

Boora, Amardeep; Ghosh, Indrajit; Chandra, Satish; Rani, K

doi:10.17159/2309-8775/2018/v60n1a1

Cited by 5 publications

(9 citation statements)

References 8 publications

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“…Following Miller’s (1961) proposal [ 17 ], later adopted by Boora et al, (2018) [ 43 ], we can utilize these differences in distributions to identify the range of speed differences in which the frequencies of the non-free-moving vehicle sub-sample exceed those of the free-moving vehicle one. If the speed difference distribution of sub-sample 2 exceeds that of sub-sample 3 within a certain interval, then there are more vehicles in sub-sample 2 with speed differences falling within that interval than there are free-moving vehicles in sub-sample 3.…”

Section: Results: Free-moving and Constrained Vehicles Analysismentioning

confidence: 99%

“…In these scenarios, the driver may maintain a specific following distance and speed that matches the vehicle in front of them. This can result in a platoon of vehicles with a more uniform speed and inter-vehicle spacing, known as following by choice or intentional platooning [ 10 , 43 ]. It is based on the driver’s autonomous decision and not on external factors, such as traffic congestion/interactions or overtaking impracticality/prohibition.…”

Section: Methods: Characterization Of Free-moving and Conditioned Veh...mentioning

confidence: 99%

“…Boora et al, in 2018 [ 43 ] identified a headway value of 10 s for free-flow conditions. They introduced a headway and relative speed distribution analysis to define a second criterion for following behavior based on the speed difference between consecutive vehicles.…”

Section: Literature Reviewmentioning

confidence: 99%

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Traffic Stream Analysis by Radar Sensors on Two-Lane Roads for Free-Moving and Constrained Vehicles Identification

Cantisani

Serrone

Mauro

et al. 2023

Sensors

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This paper focuses on the analysis of traffic streams on two-lane highways, which are crucial components of transportation networks. Traffic flow measurement technologies, such as detection stations, radar guns, or video cameras, have been used over the years to detect the level of traffic and the operating conditions. This type of sensor can record a large amount of data which is useful to evaluate and monitor road traffic conditions, and it is possible to identify free-moving and constrained vehicles by processing the collected data. This study introduces an exponential headway model to identify the headway threshold above which vehicles can be considered as unconditioned. However, this value could identify vehicles which still retain some autonomy in their speed and maneuvering. Therefore, an additional criterion to distinguish between apparently and actually conditioned vehicles has been introduced, analyzing the speed differences between a vehicle and the preceding one. Three-month sequences of traffic monitored through radar devices placed on some Italian two-lane roads have been analyzed and an exponential headway model has been introduced, as an illustrative example. The results show that introducing the criterion of maneuvering freedom can significantly improve traffic flow analysis, modifying the starting critical values of 4 and 8 s per each studied section, to 2.5 and 3 s, approaching the values suggested by international manuals for traffic flow quality analysis.

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Section: Results: Free-moving and Constrained Vehicles Analysismentioning

confidence: 99%

Section: Methods: Characterization Of Free-moving and Conditioned Veh...mentioning

confidence: 99%

See 1 more Smart Citation

Traffic Stream Analysis by Radar Sensors on Two-Lane Roads for Free-Moving and Constrained Vehicles Identification

Cantisani

Serrone

Mauro

et al. 2023

Sensors

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show abstract

“…Thirdly, the data contains a high level of unobserved heterogeneity, which may affect identifying the exact contributing factors, so the models accounting for heterogeneity in data analysis merit further deep investigation. Finally, the coupling effect of multiple factors on the severity of MME crashes was not focused on in this study, such as the existence of tunnels and bridges (Sun et al 2020), so one of the greatest future challenges is to unpack which combinations of factors produce the greatest risks (Boora et al 2018;Santos et al 2021), such as driver's risk driving behaviour and sharp curves coincided, and traffic flow and weather conditions interacted, etc.…”

Section: Discussionmentioning

confidence: 99%

What leads to severe multi-vehicle crashes on mountainous expressways in Western China?

Wang¹,

Wang²,

Sun³

2022

J. S. Afr. Inst. Civ. Eng.

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This paper investigates the occurrence and severity of collisions involving multiple vehicles on mountain expressways (MMEs) in Western China. A total of 1 521 crash samples occurring on one typical mountain expressway in Shaanxi, China, between 2012 and 2017, were analysed through a partially constrained generalised ordered logit to identify the significant risk factors contributing to the severity of such crashes. Elasticity analysis was performed to quantify the effects of each independent explanatory variable on the collision severity outcomes. Fourteen total explanatory variables were found to have a significant and pronounced influence on the likelihood of MME crashes. These include the type of collision, the at-fault driver's age, driving while fatigued, cell phone use while driving, alcohol-impaired driving, speeding, risky following and dangerous overtaking behaviour, sharp curves in the roadway and slippery pavement conditions, seasons, day of the week, time of day, and adverse weather (rain/snow/fog). The impacts of the variables on the collision severity were also explored. Taken together, the findings may serve as a useful guide for developing legislation and technical countermeasures to ensure traffic safety on mountain expressways in Western China.

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“…Bang et al [5], however, stated that free-flow speed should be determined for unobstructed vehicles based on the definition of the vehicles with headway to the nearest vehicle in front of more than 8 s and no recent or immediate meeting with a vehicle in the opposing direction. Nevertheless, according to Boora et al [6], for heterogeneous traffic conditions on multilane highways, a gap is more suitable to use than a headway as a gap does not vary due to vehicle length. A new measure called "Speed Difference" was introduced by Boora et al and was found to be suitable for identifying the free-flow conditions.…”

Section: Introductionmentioning

confidence: 99%

The Development and Assessment of Free-Flow Speed Models under Heterogeneous Traffic in Facilitating Sustainable Inter Urban Multilane Highways

et al. 2020

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The desired speed that drivers can drive without being obstructed or influenced by other road users is characterized as free-flow speed. However, free-flow speed can be influenced by other factors such as the characteristics of the vehicle, driver, road conditions, weather, and speed limits. Due to the country’s heterogeneous traffic conditions, this study aims to develop and assess free-flow speed models based on different vehicle classes and road characteristics in Malaysia. Data were sampled at 16 sites of multilane highways in Malaysia. Analyses of free-flow speed were conducted based on individual and grouped vehicle classes. Subsequently, multiple regression analyses were conducted based on these grouped vehicle classes to develop free-flow speed models. The findings show that the model with the grouping of all vehicles, which includes heavy vehicles and motorcycles, is the most suitable model as it yields the best results based on the performance indicators. The development of a free-flow speed model based on local traffic conditions, which can accurately estimate free-flow speed without having to conduct field measurements, is essential for saving time and costs in data collection. The findings from this study will contribute to improving the design of multilane highways and, ultimately, ensuring the sustainable environment of road networks.

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Measurement of free-flow conditions on multilane intercity highways under heterogeneous traffic conditions

Cited by 5 publications

References 8 publications

Traffic Stream Analysis by Radar Sensors on Two-Lane Roads for Free-Moving and Constrained Vehicles Identification

Traffic Stream Analysis by Radar Sensors on Two-Lane Roads for Free-Moving and Constrained Vehicles Identification

What leads to severe multi-vehicle crashes on mountainous expressways in Western China?

The Development and Assessment of Free-Flow Speed Models under Heterogeneous Traffic in Facilitating Sustainable Inter Urban Multilane Highways

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