Prediction of Operating Speed on Three-Dimensional Highway Alignments

Gibreel, G. M.; Easa, Said M.; El-Dimeery, I. A.

doi:10.1061/(asce)0733-947x(2001)127:1(21)

Cited by 105 publications

(38 citation statements)

References 2 publications

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“…Nevertheless, some relevant research on this field has been conducted to account for the simultaneous effect of the horizontal and vertical alignments on driving behavior. The research conducted by Fitzpatrick et alo (14) and Gibreel et alo (15) proposed speed models categorized by vertical alignment conditions. Donnell et alo (16) modeled the speed of trucks in horizontal curves; they took into account the grades of the approach and departure tangents.…”

mentioning

confidence: 99%

Free-Flow Speed Model Based on Portuguese Roadway Design Features for Two-Lane Highways

Lobo

Rodrigues

Couto

2013

Transportation Research Record: Journal of the Transportation R

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Speed is a key performance measure in economic and environrnental analyses of two-lane highways. Speed, combined with the percentage of time spent following, is also used in the assessment of levei of service.Under free-ftow conditions, the circulation of a given vehicle is not con- Speed is a major factor in the assessment of road performance. Depending on the functional classification of a given road, a design speed is established, and engineers define the geometric features of the road to ensure that drivers can, in normal traffic conditions, achieve the expected average travei speed to reach their destinations on time. Furthermore, an operating speed may be estimated for performance evaluation during the road operation period. Real environment speed measurements are required, and the operating speed is typically associated with the 85th percentile of the observed speed distribution (1). Speed is usually recognized by road planners, designers, and users as an important measure for the evaluation ofthe levei of service, speed limit defínition, design consistency and safety analyses, and other essential studies.Recognizing the role of speed in road performance evaluation, the Highway Capacity Manual 2010 (HCM) (2) recommends speed as the most appropriate concept for use in the economic DC, 2013, pp. 12-18. DOI: 10.3141/2348 and environmental analyses of two-Iane highways, including the assessment of the impact on air quality and noise leveI. ln addition, the HCM methodology to assess the levei of service of this type of road also uses the average travei speed as an input, which in tum depends on the free-flow speed (FFS) and on the traffic volume. ln other words, the average travei speed adds the effects of the delays caused by the remaining traffic to the FFS. The FFS reflects the drivers' response to the road's geometric and environmental features because drivers are not affected by the presence of other vehicles. The definition of the FFS proposed by the HCM is similar to the definition of operating speed given by the AASHTO Green Book (1). However, operating speed may also be affected by drivers' perception of risk, speed limit and enforcement, general driving practices and culture, and vehicle technology. For this reason, speed prediction models have been developed in different regions worldwide and in different time periods.Reference manuals and national guides for road design usually define operating speed for a road section rather than for specific design elements. The HCM (2) establishes a base FFS as the speed observed for roads presenting no access points and lane and shoulder widths equal to or greater than 3.6 m and 1.8 m, respectively. The HCM also provides an FFS estimation model, taking into account speed reductions to the base FFS caused by smaller cross sections and higher densities of access points.The AASHTO Green Book (1) also provides recommendations for design and operating speeds. Different design speeds are suggested according to the functional classification intended for a planned ro...

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confidence: 99%

Free-Flow Speed Model Based on Portuguese Roadway Design Features for Two-Lane Highways

Lobo

Rodrigues

Couto

2013

Transportation Research Record: Journal of the Transportation R

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“…Nevertheless, studies by, e.g., Fitzpatrick et al (2000a) and Gibreel et al (2001) focused on the simultaneous effects of the horizontal and vertical alignments, proposing speed models categorized by vertical alignment conditions. Donnell et al (2001) studied the primary influence of the grade on truck speeds, developing speed models for horizontal curves that account for the effects of the grades of the approach and departure tangents.…”

Section: Literature Frameworkmentioning

confidence: 99%

“…Other less used speed predictors include the element extension (Krammes et al 1995;Voigt and Krammes 1996;Cardoso 1996;Schurr et al 2002), the superelevation rate (Voigt and Krammes 1996;Gibreel et al 2001;Bonneson et al 2007), and the posted speed limit (Lamm et al 1988;Schurr et al 2002).…”

Section: Literature Frameworkmentioning

confidence: 99%

Flexible Stochastic Frontier Approach to Predict Spot Speed in Two-Lane Highways

2016

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The approach to spot speed prediction in two-lane highways followed in this study aims to evaluate the effects of a comprehensive set of speed factors, with a special focus on the geometric characteristics of the road segment to which the element belongs. Two flexible models were developed for different types of roads based on a stochastic frontier formulation in which the maximum operating speed is estimated as a function of road geometrics and the one-sided disturbance accounts for diversity in driving behavior and vehicle characteristics, allowing the estimation of any percentile speed. The models are applicable to horizontal curves and tangents and consider both on-site characteristics and aggregated variables characterizing the road segment. The results show a clear influence of segment features on different percentile spot speeds, revealing that recent driving experience and expectations about the quality of the geometric design influence the way a driver approaches a specific road element. Additionally, this study contributes to addressing some of the limitations of existing speed models identified in 2 the literature.

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“…In most cases, data collection device is a manually operated radar gun or similar [6]. The use of radar gun has three important problems: human error, cosine error and drivers' behaviour affection.…”

Section: Introductionmentioning

confidence: 99%

“…In order to deal with this issue, it is necessary to collect data from a huge sample of people driving along a sample of elements. Speed data can be obtained by using either spot or continuous collection methodologies.In most cases, data collection device is a manually operated radar gun or similar [6]. The use of radar gun has three important problems: human error, cosine error and drivers' behaviour affection.…”

mentioning

confidence: 99%

Application of global positioning system and questionnaires data for the study of driver behaviour on two‐lane rural roads

Pérez-Zuriaga

Torregrosa

Campoy-Ungría

et al. 2013

IET Intelligent Transport Systems

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ABSTRACT:Methodologies based on naturalistic observation provide the most accurate data for studying drivers' behaviour. This paper presents a new methodology to obtain naturalistic data related to drivers' behaviour in a road segment. It is based on the combination of using global positioning system data and drivers' questionnaires. The continuous speed profiles along a road segment and the characteristics of drivers, of their trips and the type of their vehicles can be obtained for a great amount of drivers. It has already been successfully used for several studies, such as the development of models to estimate operating speed profile in two-lane rural road segments; or the characterization of driving styles. These operating speed models have been the key for the development of a new geometric design consistency model, allowing an easier road safety evaluation. Besides, knowledge on the human factors that influence speed choice may be useful for road safety media campaigns and education programs designers, and also for the improvement of intelligent driver assistance systems. 2 INTRODUCTIONMultiple factors typically combine to produce circumstances that lead a vehicle to crash. The main concurrent factors are human factors, roadway environment factors, and vehicle factors. According to the research by Treat et al. [1], human factors are the most prevalent contributing factor of crashes, being present on the 93 % of crashes; followed by roadway (34 %) and vehicle factors (13 %).However, due to its characteristics, it is also the most complicated factor to study. The best results in this area have been achieved by using data collection methodologies based on naturalistic observation. This kind of methodologies is based on subjects driving the way they usually do, in their own vehicles and without any specific instructions or interventions. Whereas 100-Cars Naturalistic Driving Study was focused on drivers' behaviour at crash situations, the central goal of SHRP2 Naturalistic Driving Study is the study of how the driver interacts with and adapts to the vehicle, traffic environment, roadway characteristics, traffic control devices, and the environment. It also includes assessing the changes in collision risk associated with each of these factors and interactions.This research is involving more than 3000 volunteer drivers, who are monitored for a three year period, beginning in 2010.Both previous research mainly study passenger car drivers' behaviour. 2 Be Safe aims to understand and characterize powered two wheeler (PTW) rider behaviour. This is the world's first naturalistic riding study involving instrumented PTWs.In most of that kind of studies, drivers are volunteers who know the scope of the research project, so their behaviour may be biased. Besides, they mainly focus on drivers' behaviour at crash situations, which are rare events. For characterizing drivers' behaviour, the most studied variable is the speed at which they drive at different road alignment elements (curves, tangents and spiral transitions) a...

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Prediction of Operating Speed on Three-Dimensional Highway Alignments

Cited by 105 publications

References 2 publications

Free-Flow Speed Model Based on Portuguese Roadway Design Features for Two-Lane Highways

Free-Flow Speed Model Based on Portuguese Roadway Design Features for Two-Lane Highways

Flexible Stochastic Frontier Approach to Predict Spot Speed in Two-Lane Highways

Application of global positioning system and questionnaires data for the study of driver behaviour on two‐lane rural roads

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