Speed Factors on Low-Volume Roads for Horizontal Curves and Tangents

Dell’Acqua, Gianluca; Russo, Francesca

doi:10.3846/bjrbe.2010.13

Cited by 34 publications

(14 citation statements)

References 9 publications

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“…The obtained MAD, RMSE and I values are 3.28, 3.35 and 0.05, respectively. For the V 85 prediction model validation, researchers have reported values of MAD ranging from 4.44 to 15.00 and RMSE from 3.92 to 19.2 are satisfactory (Pérez-Zuriaga et al 2010;Dell' Acqua, Russo 2010, Esposito et al 2011Jacob, Anjaneyulu 2013). Lower MAD and RMSE values indicate lesser error between predicted and actual V 85 values.…”

Section: Model Validationmentioning

confidence: 99%

Operating Speed Prediction Model as a Tool for Consistency Based Geometric Design of Four-Lane Divided Highways

et al. 2019

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Researchers have studied two-lane rural highways to predict the operating speed on horizontal curves and correlated it with safety. However, the driving characteristics of four-lane-divided highways are different. Weak lane discipline is observed in these facilities, which influences vehicle speed in adjacent lane or space. So, irrespective of its lane or lateral position, vehicles in four-lane divided highways are considered free flowing only when it maintains the minimum threshold headway from any lead vehicle. Examination of two conditions is proposed to ensure the free flow. Vehicles meeting both conditions, when tracked from the preceding tangent section till the centre of the horizontal curve, are considered as free flowing. The speed data of such free flowing passenger cars at the centre of eighteen horizontal curves on four-lane divided highways is analysed to develop a linear operating speed prediction model. The developed model depends on curve radius and preceding tangent length. The operating speed of passenger car in four-lane divided highways is influenced by horizontal curve of radius 360 m or less. Further, longer tangent would yield higher operating speed at the centre of the curve. Finally, two nomograms are suggested for conventional design, consistency based design and geometric design consistency evaluation of four-lane divided horizontal curves.

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Section: Model Validationmentioning

confidence: 99%

Operating Speed Prediction Model as a Tool for Consistency Based Geometric Design of Four-Lane Divided Highways

et al. 2019

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“…Dell'Acqua and Russo studied driver speed behavior on undivided low-volume roads without spiral transition curves between tangents and circular curves (14). They identified transition regions and assessed deceleration and acceleration rates for each curve.…”

Section: Serbian and Italian Case Studiesmentioning

confidence: 99%

Driver Speed Behavior on Circular Curves of Undivided Two-Lane Rural Roads

Russo

Fric

Biancardo

et al. 2015

Transportation Research Record: Journal of the Transportation R

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Many researches have proved that one of the parameters that most influence the safe driving is the operating speed defined as the speed at which drivers travel on a dry road in free flow conditions during daylight hours. This study describes a comparison between the driver speed behavior on horizontal circular curves located in Serbia and the driver speed behavior on circular curves located in Italy with analogous infrastructural-geometric contexts. Only curves falling within two-lane rural roads network in low-volume conditions without spiral transition curves have been studied. Operating speed profiles were plotted and a careful analysis was carried out to study the deceleration/acceleration motion at each selected curve. Speed measurements were conducted by using different devices: a) for Italian case, laser detectors were used that emit and receive a pair of laser beams perpendicularly to the road’s axis and they record the instantaneous vehicle speed; b) for Serbian case, sensors were used with an applicant software developed in the LabVIEW programming environment and signals logged in a binary file for which the vehicle speed is measured on basis of the passing time between two consecutive sensors along the curve. Two driver behavior types were found: a) drivers that decelerate approaching the middle of the curve and accelerate leaving it; b) drivers that decelerate on the whole circular curve length. T-test was performed. Statistically, no significant difference was produced from the analysis when circular curves are located in different states which reflect the same geometric, traffic and environmental context

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“…The aim of the refined study of driver speed behavior on rural roads under low-volume conditions described here is to update previous research work in which four operating speed prediction models were developed for tangents and circular curves (5). New variables that can influence driver speed behavior, such as pavement distress, were used in the regression equations in the experimental analysis.…”

Section: Road Performance Evaluation Using Geometric Consistency and Pavement Distress Datamentioning

confidence: 99%

Road Performance Evaluation Using Geometric Consistency and Pavement Distress Data

Dell’Acqua

Russo

2011

Transportation Research Record: Journal of the Transportation R

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Many studies on driver speed behavior are found in the scientific literature today, and various researchers have addressed roadway alignment consistency for travel safety in the context of current operating speeds. An experimental analysis of low-volume roads without spiral transition curves between geometric tangent and circular elements on the horizontal alignment was conducted in southern Italy. All selected roadways are located in areas with level terrain and vertical grades of less than 6%. This study is a continuation of a 2009 research project that developed procedures to predict speed factors for horizontal curves and tangents on low-volume roads. The present research focuses on the design of continuous operating speed profiles that reproduce real driver speed behavior at each section of the horizontal alignment with variables that now include the pavement deterioration condition. Four new regression equations were developed to predict the operating speed on tangent and circular curve elements by using speed factors and geometric variables. These models were developed by a traditional ordinary least-squares method involving speed values not surveyed in transition zones. The aim of this refined study is to illustrate the roadway factors influencing optimal and safe driving performance.

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Speed Factors on Low-Volume Roads for Horizontal Curves and Tangents

Cited by 34 publications

References 9 publications

Operating Speed Prediction Model as a Tool for Consistency Based Geometric Design of Four-Lane Divided Highways

Operating Speed Prediction Model as a Tool for Consistency Based Geometric Design of Four-Lane Divided Highways

Driver Speed Behavior on Circular Curves of Undivided Two-Lane Rural Roads

Road Performance Evaluation Using Geometric Consistency and Pavement Distress Data

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