Exploration of the Relationships between Operating Speed and Roadway Features on Tangent Sections

Fitzpatrick, Kay; Miaou, Shaw-Pin; Brewer, Marcus A; Carlson, Paul J; Wooldridge, M D

doi:10.1061/(asce)0733-947x(2005)131:4(261)

Cited by 55 publications

(37 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is the case, for instance, in research by Fitzpatrick et al (6,7), Crisman and Perco (8), and Abdul-Mawjoud and Sofia (9). None of these studies describes the approach adopted to identify this headway value as the headway associated with free-flow vehicles on two-lane highways.…”

Section: Free-gap Evaluation For Two-lane Rural Highwaysmentioning

confidence: 90%

Free-Gap Evaluation for Two-Lane Rural Highways

Lobo

Jacques

Rodrigues

et al. 2011

Transportation Research Record: Journal of the Transportation R

View full text Add to dashboard Cite

Operating speed is most frequently represented by the 85th percentile speed (V 85 ) of vehicles passing at a given road location, in a nonplatoon condition, and it is usually determined by spot speed measurements. The Highway Capacity Manual (HCM) 2000 recommends that the number of observations for V 85 calculation be equal to or greater than 100 (3). Therefore, one critical issue for studies of operating speeds is to define when a platoon condition is present. Another relevant question is related to the identification of the road volume for which the number of vehicles in a nonconstrained operation is enough for V 85 estimation.In most studies on the development of operating speed prediction models, a nonplatoon condition is usually defined by means of minimum headway between successive vehicles in a traffic stream. However, these studies do not describe the procedure adopted to establish the reference value taken. Also, this traffic measure is affected by the type of the two successive vehicles considered. Equipment available for automatic speed data collection is, in some cases, able to collect headway and gap values simultaneously. The gap between two successive vehicles, being the interval between the rear bumper of the first vehicle and the front bumper of the second as the vehicles pass a point on the roadway, is not affected by the vehicles' type. Therefore, the definition of platoon condition based on gap values can be useful for general applications.In this context, this paper aims to present and test a procedure to define a gap value between two successive vehicles from which the vehicles can be considered as traveling in a nonplatoon condition. This reference value is referred to as "free gap." In addition, the procedure allows for the identification of the traffic volume suitable for ensuring the sample size required for V 85 measurements. Therefore, the procedure is proposed as the initial activity to be performed for V 85 data collection for operating speed evaluation and modeling. This paper is organized into five sections. After this introductory section, a brief literature review is presented on headway reference values considered for platoon definition in different operating speed studies. The third and fourth sections describe, respectively, the procedure proposed and its application to Portuguese conditions. This application is the initial step for a broad operating speed data collection activity planned to be performed at Portuguese roads for the development of a respective operating speed prediction model. The last section presents this study's main conclusions. Platoon Definition for oPerating SPeeD MeaSureMentSAlthough there is not one definition for platoon, this term is commonly applied to a group of vehicles traveling together in which the vehicles behind the leading vehicle are usually not at their desired Free-Gap Evaluation for Two-Lane Rural HighwaysAntónio Lobo, Maria Alice Prudêncio Jacques, Carlos Manuel Rodrigues, and António Couto Studies related to operating speed predicting...

show abstract

Section: Free-gap Evaluation For Two-lane Rural Highwaysmentioning

confidence: 90%

Free-Gap Evaluation for Two-Lane Rural Highways

Lobo

Jacques

Rodrigues

et al. 2011

Transportation Research Record: Journal of the Transportation R

View full text Add to dashboard Cite

show abstract

“…Most existing models have been developed for a specific type of road section or single/multiple geometric elements. Operating speed models currently in use include horizontal circular curve models, 11,12 straight road models, 13 curved slope models, 14,15 desired speed models, 16 roadside interference models, 17 and traffic impact models. 18 In addition to these models, Russo et al 19 developed a predicting model to be used at the same time on tangents and circular curves.…”

Section: Literature Reviewmentioning

confidence: 99%

New design method for horizontal alignment of complex mountain highways based on “trajectory–speed” collaborative decision

Jin

Lin

Shao

2017

Advances in Mechanical Engineering

View full text Add to dashboard Cite

The safety evaluation of geometry features design based on actual driving behavior has always been a basic concept of highway design. However, current design methods, including both the design speed method and operating speed method, are still far away from real-world driving conditions. In this work, we propose a new alignment design method which can take into account typical handing patterns (driving styles) of human drivers and can pay special attention to dangerous driving behaviors. The core of the proposed method is forecasting the trajectories of typical direction control patterns within roadway width, which can be used by drivers. Then, forecast the driving speed of typical speed control patterns on the basis of the curvature of the preview trajectory just determined. Mathematical programming method was used in this study, whereby the objective functions and constraints were developed to model the typical driving patterns. This article provided five direction control patterns and four speed control patterns to designers so that they could select an appropriate pattern to predict the trajectory and speed for the designed road. Finally, the trajectory and speed are used to control the geometric features of the road. Geometric features can determine the driveway shape, such as curve radius, deflection angle, spiral length, tangent length, roadway/lane/shoulder width, and any or all of these can be adjusted by the designer. Meanwhile, as more than one driving pattern is optional and vehicle performance, driving stability, and ride comfort restrictions are introduced to trajectory/speed decision-making, the new method more closely approximates to real-world driving than conventional methods. The application example shows that the proposed method is especially suitable for the horizontal alignment design of low/medium design speed highways that traverse rugged terrain.

show abstract

“…Inclusion of operating speed in the design phase and the evaluation of the road alignment consistency is in the focus of many significant researches in recent years (Gibreel et al 1999(Gibreel et al , 2001Ottesen, Krammes 2000;Hassan 2004;Fitzpatrick et al 2005;Marchionna, Perco 2008;Perco 2008;Medina, Tarko 2005;Cafiso, Cerni 2012;Wang et al 2013).…”

Section: Data Collectionmentioning

confidence: 99%

Detection and analysis of hazardous locations on roads: a case study of the Croatian motorway A1

Cvitanić

Vukoje

2017

Transport

View full text Add to dashboard Cite

Abstract. The present paper describes research undertaken to identify causes underlying single-vehicle accidents (in terms of road design, driver behaviour and vehicle handling characteristics), which continuously happen in one specific section of Croatian motorway A1. The research resulted in a proposed procedure for a detection of hazardous locations on motorways and analysis of possible causes of single-vehicle accidents. The main part of the procedure involves test-rides with a vehicle equipped with devices (a ball bank indicator and a GPS data logger), which collect data on driver's behaviour and vehicle handling characteristics (position, speed, longitudinal and lateral acceleration, heading, path radius, etc.). Despite the fact that the motorway was designed in accordance with the design guidelines, test rides performed by higher operating speeds identified two locations with a lateral acceleration change a few times higher than the design value. The collected data are then used for analysing hypotheses about the possible causes of accidents by using a vehicle dynamic model. The hypothesis that a sudden change in lateral acceleration could result in a driver's inadequate manoeuvre like braking and cause a vehicle accident was analysed with a transient bicycle model. The results of test rides and the transient bicycle model indicate that speed, intensity of deceleration and underinflated tires significantly affect the probability of a single-vehicle accident.

show abstract

Exploration of the Relationships between Operating Speed and Roadway Features on Tangent Sections

Cited by 55 publications

References 1 publication

Free-Gap Evaluation for Two-Lane Rural Highways

Free-Gap Evaluation for Two-Lane Rural Highways

New design method for horizontal alignment of complex mountain highways based on “trajectory–speed” collaborative decision

Detection and analysis of hazardous locations on roads: a case study of the Croatian motorway A1

Contact Info

Product

Resources

About